Exhibit
10.15


 


FORM
OF WARRANT AGENT AGREEMENT


 


THIS
WARRANT AGENT AGREEMENT (this “Agreement”) is dated April [ ], 2021, between PROTAGENIC THERAPEUTICS, INC.,
a Delaware corporation (the “Company”), and AMERICAN STOCK TRANSFER & TRUST COMPANY, LLC, acting as warrant
agent (the “Warrant Agent”).


 


WHEREAS,
the Company proposes to issue common stock purchase warrants (the “Warrants”) to acquire one share of
common stock, par value $0.000001 per share (“Common Stock”), subject to adjustment as provided herein,
of the Company (collectively, the “Warrant Shares”);


 


WHEREAS,
each Warrant shall represent the right to purchase from the Company, at an initial price of $[ ] per share 120% of the public
offering price (the “Exercise Price”), one share of Common Stock, subject to adjustment as provided hereunder; and


 


WHEREAS,
American Stock Transfer & Trust Company, LLC is willing to serve as the Warrant Agent in connection with the issuance of Warrant
Certificates (as defined below) and the other matters as provided herein.


 


NOW,
THEREFORE, in consideration of the foregoing and for the purpose of defining the terms and provisions of the Warrants and the
respective rights and obligations thereunder of the Company, the Warrant Agent and the record holders from time to time of the
Warrants or, if the Warrants are held in “street name,” a Participant (as defined below) or a designee appointed by
such Participant (each, a “Holder” and collectively, the “Holders”), the parties hereby
agree as follows:


 


1.
Definitions. For the purposes hereof,
the following terms shall have the following meanings:


 


“Aggregate
Exercise Price” means, with respect to each exercise of Warrants held by the Holder, the Exercise Price multiplied by
the aggregate number of Warrant Shares (which must be a whole number) that such Holder intends to purchase pursuant to such exercise.


 


“Business
Day” means any day except Saturday, Sunday and any day which shall be a federal legal holiday in the United States or
a day on which banking institutions in The City of New York are authorized or required by law or other government action to close.


 


“Common
Stock” shall have the meaning set forth in the first WHEREAS clause.


 


“Date
of Exercise” means the date on which the Holder shall have delivered to the Warrant Agent an appropriately completed
and duly signed Form of Election to Purchase (with the Warrant Shares Exercise Log attached to it and reference to the relevant
Warrant Certificate sufficient to identify it).


 


“Exchange
Act” means the Securities Exchange Act of 1934, as amended, and the rules and regulations of the Securities and Exchange
Commission (the “Commission”) promulgated thereunder.


 




    	 



    	 



    

 


“Exercise
Price” shall have the meaning set forth in the second WHEREAS clause.


 


“Expiration
Date” means April [  ], 2026.


 


“Form
of Election to Purchase” means a Form of Election to Purchase substantially in the form attached to the Warrant.


 


“Initial
Exercise Date” means April [  ], 2021.


 


“Initial
Issuance Date” means April [  ], 2021.


 


“Person”
means a corporation, association, partnership, limited liability corporation, organization, business, individual, trust, government
or political subdivision thereof or governmental agency.


 


“Prospectus”
means the final prospectus relating to the Warrant Shares included in the Registration Statement.


 


“Redemption
Date” shall have the meaning set forth in Section 8(b).


 


“Redemption
Price” shall have the meaning set forth in Section 8(b).


 


“Registration
Statement” means, collectively, the various parts of the registration statement prepared by the Company on Form S-1 (File No.
333-253006) with respect to the Warrant Shares, each as amended as of the date hereof, including the Prospectus therein and all
exhibits filed with such registration statement.


 


“Securities
Act” means the Securities Act of 1933, as amended.


 


“Trading
Day” means (i) a day on which the shares of Common Stock are traded on the Trading Market on which the shares of Common
Stock are then listed or quoted, or (ii) if the shares of Common Stock are not listed on any such Trading Market, a day on which
the shares of Common Stock are traded in the over-the-counter market, as reported by the OTC Markets; provided, that in the event
that the shares of Common Stock are not listed or quoted as set forth in clause (i) or (ii) hereof, then Trading Day shall mean
a Business Day.


 


“Trading
Market” means the New York Stock Exchange, the NYSE American, the Nasdaq Capital Market, the Nasdaq Global Market or
the Nasdaq Global Select Market.


 


“VWAP”
means, for any date, the price determined by the first of the following clauses that applies: (a) if the Common Stock is then
listed or quoted on a Trading Market, the daily volume weighted average price of the Common Stock for such date (or the nearest
preceding date) on the Trading Market on which the Common Stock is then listed or quoted as reported by Bloomberg L.P. (based
on a Trading Day from 9:30 a.m. (New York City time) to 4:02 p.m. (New York City time)), (b) if OTCQB or OTCQX is the principal
market on which the Common Stock is traded, the volume weighted average price of the Common Stock for such date (or the nearest
preceding date) on OTCQB or OTCQX as applicable, (c) if the Common Stock is not then listed or quoted for trading on OTCQB or
OTCQX and if prices for the Common Stock are then reported on the OTC (“Pink”) Markets (or a similar organization
or agency succeeding to its functions of reporting prices), the most recent bid price per share of the Common Stock so reported,
or (d) in all other cases, the fair market value of a share of Common Stock as determined by an independent appraiser selected
in good faith by the holders of a majority in interest of the Warrants then outstanding and reasonably acceptable to the Company,
the fees and expenses of which shall be paid by the Company.


 




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“Warrant
Certificate” means a certificate in substantially the form attached hereto as Exhibit A representing such number
of Warrants set forth on the Warrant Certificate.


 


“Warrants”
shall have the meaning set forth in the first WHEREAS clause.


 


“Warrant
Shares” shall have the meaning set forth in the first WHEREAS clause.


 


2.
Form of Warrant.


 


(a)
Warrants in Global Form. The Warrants
shall initially be issuable in book-entry registration only and evidenced by one or more global Warrant Certificates (the “Global
Warrant Certificates”) deposited with the Depository Trust Company (the “Depository”) and registered
in the name of Cede & Co. (“Cede”), a nominee of the Depository. Ownership of beneficial interests in the
Warrants shall be shown on, and the transfer of such ownership shall be effected through, records maintained by (i) the Depository
or its nominee for each Global Warrant Certificate or (ii) institutions that have accounts with the Depository (such institutions,
with respect to a Warrant in its account, each a “Participant”). For purposes of this Agreement, the delivery
of a notice from the Depository or a Participant of the transfer or exercise of Warrants in the form of a Global Warrant Certificate
shall be deemed to constitute the delivery of a Warrant Certificate with respect to such transfer or exercise. If the Depository
subsequently ceases to make its book-entry settlement system available for the Warrants, the Company may instruct the Warrant
Agent regarding other arrangements for book-entry settlement. If the Company determines, in its sole discretion, not to have securities
represented by the Global Warrant Certificates, the Company will instruct the Warrant Agent to prepare and deliver physical certificates
evidencing the Warrants in exchange for the beneficial interests in the Global Warrant Certificates, based on directions received
by the Depository from its Participants with respect to ownership of beneficial interests in the Global Warrant Certificates.
In such event, any physical certificates evidencing the Warrants shall represent one or more Warrants as set forth on the Warrant
Certificate and be issued in registered form only as definitive Warrant Certificates and shall be substantially in the form attached
hereto as Exhibit A, shall be dated the date of issuance thereof (whether upon initial issuance, register of transfer, exchange
or replacement) and shall bear such legends and endorsements typed, stamped, printed, lithographed or engraved thereon as the
Company may deem appropriate and as are not inconsistent with the provisions of this Agreement.


 


(b)
Effect of Signature. Warrant Certificates
shall be signed by, or bear the facsimile or electronic signature of, the chief executive officer, president, chairperson of the
board, chief financial officer, treasurer, any vice president, or secretary of the Company. In the event the person whose facsimile
or electronic signature has been placed upon any Warrant Certificate shall have ceased to serve in the capacity in which such
person signed the Warrant Certificate before such Warrant Certificate is issued, it may be issued with the same effect as if he
or she had not ceased to be such at the date of issuance.


 




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(c)
Effect of Countersignature. Unless and
until countersigned by the Warrant Agent pursuant to this Agreement, a Warrant Certificate shall be invalid and of no effect and
may not be exercised by the holder thereof. Such signature by the Warrant Agent upon any Warrant Certificate executed by the Company
shall be conclusive evidence that such Warrant Certificate has been duly issued under the terms of this Agreement.


 


(d)
Warrant Register. The Warrant Agent shall
maintain books (the “Warrant Register”), for the registration of original issuance and the registration of
transfer of the Warrants. Upon the initial issuance of the Warrants, the Warrant Agent shall issue and register the Warrants in
the names of the respective holders thereof in such denominations and otherwise in accordance with instructions delivered to the
Warrant Agent by or on behalf of the Company. The Company and the Warrant Agent may deem and treat the registered Holder of each
Warrant Certificate as the absolute owner of the Warrants represented thereby for the purpose of any exercise thereof or any distribution
to the Holder, and for all other purposes, absent actual notice to the contrary. Any Person in whose name ownership of a beneficial
interest in the Warrants evidenced by a Global Warrant Certificate is recorded in the records maintained by the Depository or
its nominee shall be deemed the “beneficial owner” thereof; provided, that all such beneficial interests shall be
held through a Participant, which shall be the registered holder of such Warrants.


 


(e)
Registration of Transfers. The Warrant
Agent shall register the transfer of any portion of a Warrant Certificate in the Warrant Register, upon surrender of the Warrant
Certificate, with the Form of Assignment attached thereto, to the Warrant Agent at its address specified for notice set forth
in Section 14 below. Upon any such registration or transfer, a new Warrant Certificate substantially in the form attached hereto
as Exhibit A (any such new Warrant Certificate, a “New Warrant Certificate”), evidencing the portion of the
Warrant Certificate so transferred shall be issued to the transferee and a New Warrant Certificate evidencing the remaining portion
of the Warrant Certificate not so transferred, if any, shall be issued to the transferring Holder. Upon issuance and delivery
of the New Warrant Certificate, the Warrant Certificate surrendered to the Warrant Agent shall be clearly marked “cancelled”
or bear a similar statement to that effect. The delivery of the New Warrant Certificate by the Warrant Agent to the transferee
thereof shall be deemed to constitute acceptance by such transferee of all of the rights and obligations of a holder of a Warrant
Certificate. Notwithstanding the foregoing, so long as the Warrants are evidenced by Global Warrant Certificates deposited with
the Depository, ownership of beneficial interests in the Warrants shall be shown on, and the transfer of such ownership shall
be effected through, records maintained (i) by the Depository or its nominee for each Warrant; (ii) by Participants; or (iii)
directly on the book-entry records of the Warrant Agent with respect only to owners of beneficial interests that represent such
direct registration.


 


(f)
Warrants in Uncertificated Form. Notwithstanding
the foregoing and anything else herein to the contrary, the Warrants may be issued in uncertificated form if so specified by the
Company.


 




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3.
Term of Warrants. Warrants shall be exercisable
by the registered Holder at any time and from time to time on or after the Initial Exercise Date until 5:00 p.m. (New York time)
on the Expiration Date. At 5:00 p.m. (New York time) on the Expiration Date, any Warrant not exercised prior thereto (including
without limitation, by payment of the applicable Aggregate Exercise Price on or prior to 5:00 p.m. (New York time) on the Expiration
Date) shall be and become void and of no value.


 


4.
Exercise of Warrants and Delivery of Warrant
Shares.


 


(a)
Exercise Procedure. At such times, and
upon such representations and agreements, upon delivery of an appropriately completed and duly signed Form of Election to Purchase
(with the Warrant Shares Exercise Log attached and reference to the applicable Warrant Certificate sufficient to identify it)
to the Warrant Agent (or, in the case of a Global Warrant Certificate, properly delivered by the Participant in accordance with
the Depository’s procedures), at its address for notice set forth in Section 14, and payment of the Aggregate Exercise Price
by the date that is one (1) Trading Day after the Date of Exercise, the Company shall, on or prior to the date that is the later
of (A) the date that is three (3) Trading Days after the Date of Exercise and (B) the date that is two (2) Trading Days after
the date on which the Aggregate Exercise Price has been paid in accordance with Section 10 below (such later date, the “Warrant
Share Delivery Date”), (i) provided that the Company’s transfer agent (the “Transfer Agent”)
is participating in the Depository’s Fast Automated Securities Transfer Program and an effective registration statement
is available for the issuance of the Warrant Shares, or (ii) if the Transfer Agent is not participating in the Depository’s
Fast Automated Securities Transfer Program, issue and dispatch by overnight courier to the address as specified in the Form of
Election to Purchase, a certificate, registered in the Company’s share register in the name of the Holder or its designee,
for the number of shares of Common Stock to which the Holder is entitled pursuant to such exercise. Any Person so designated by
the Holder to receive Warrant Shares shall be deemed to have become holder of record of such Warrant Shares as of the time that
the Holder shall have delivered to the Warrant Agent an appropriately completed and duly signed Form of Election to Purchase (with
the Warrant Shares Exercise Log attached to it and reference to the relevant Warrant Certificate sufficient to identify it), provided
that the Holder delivers the Aggregate Exercise Price by the date that is one (1) Trading Day after the Date of Exercise.


 


(b)
If the Holder delivers a Form of Election to
Purchase but fails, within one Trading Day after the Date of Exercise, to deliver the Aggregate Exercise Price, then the Holder
shall only be deemed to be the holder of record of the Warrant Shares upon delivery of the Aggregate Exercise Price, so long as
such Aggregate Exercise Price is delivered within three (3) Trading Days of the Date of Exercise.


 


(c)
No ink-original Form of Election to Purchase
shall be required, nor shall any medallion guarantee (or other type of guarantee or notarization) of any Form of Election to Purchase
be required. Notwithstanding anything herein to the contrary, the Holder shall not be required to physically surrender any Warrant
Certificate to the Company or Warrant Agent until all of the Warrant Shares issuable thereunder have been purchased and all of
the Warrants evidenced by such Warrant Certificate have been exercised in full, in which case, the Holder shall surrender such
Warrant Certificate to the Company or Warrant Agent for cancellation within five (5) Trading Days of the date the final Form of
Election to Purchase is delivered to the Warrant Agent. Partial exercises of such Warrant Certificate resulting in purchases of
a portion of the total number of Warrant Shares available thereunder shall have the effect of lowering the outstanding number
of Warrant Shares purchasable thereunder in an amount equal to the applicable number of Warrant Shares purchased. The Holder
and any assignee, by acceptance of a Warrant Certificate, acknowledge and agree that, by reason of the provisions of this subsection,
following a partial exercise of such Warrant Certificate, the number of Warrant Shares issuable upon exercise of such Warrant
Certificate at any given time may be less than the amount stated on the face thereof.


 




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(d)
If fewer than all Warrant Shares issuable upon
exercise of the relevant Warrant Certificate are purchased upon any exercise thereof, then promptly following the date on which
the Holder has taken all actions necessary under the terms of this Agreement for such Holder to receive Warrant Shares and be
deemed to have become the holder of record of such Warrant Shares and at the request of the Holder (provided that the Holder has
delivered the original physical Warrant Certificate to the Warrant Agent for cancellation), the Company will execute and deliver
to the Holder or its assigns a New Warrant Certificate (dated the date such Holder is deemed to have become the holder of record
of such Warrant Shares) evidencing the unexercised portion of the relevant Warrant Certificate. If fewer than all the Warrants
evidenced by a Global Warrant Certificate are exercised, a notation shall be made to the records maintained by the Depository,
its nominee for each Global Warrant Certificate, or a Participant, as appropriate, evidencing the balance of the Warrants remaining
after such exercise.


 


(e)
In addition to any other rights available to
the Holder, if the Holder has taken all actions necessary under the terms of this Agreement for such Holder to receive Warrant
Shares subject to a Form of Election to Purchase on a Warrant Share Delivery Date and the Company fails, or fails to cause the
Warrant Agent, to transmit to the Holder the Warrant Shares in accordance with the provisions of subsection 4(a) above on or before
the applicable Warrant Share Delivery Date, and if after such date the Holder is required by its broker to purchase (in an open
market transaction or otherwise) or the Holder’s brokerage firm otherwise purchases, shares of Common Stock to deliver in
satisfaction of a sale by the Holder of the Warrant Shares which the Holder anticipated receiving upon such exercise (a “Buy-In”),
then the Company shall (A) pay in cash to the Holder the amount, if any, by which (x) the Holder’s total purchase price
(including brokerage commissions, if any) for the shares of Common Stock so purchased exceeds (y) the amount obtained by multiplying
(1) the number of Warrant Shares that the Company was required to deliver to the Holder in connection with the exercise at issue
times (2) the price at which the sell order giving rise to such purchase obligation was executed, and (B) at the option of the
Holder, either reinstate the portion of the Warrant and equivalent number of Warrant Shares for which such exercise was not honored
(in which case such exercise shall be deemed rescinded) or deliver to the Holder the number of shares of Common Stock that would
have been issued had the Company timely complied with its exercise and delivery obligations hereunder. For example, if the Holder
purchases shares of Common Stock having a total purchase price of $11,000 to cover a Buy-In with respect to an attempted exercise
of shares of Common Stock with an aggregate sale price giving rise to such purchase obligation of $10,000, under clause (A) of
the immediately preceding sentence the Company shall be required to pay the Holder $1,000. The Holder shall provide the Company
written notice indicating the amounts payable to the Holder in respect of a Buy-In and evidence of the amount of such loss.


 


(f)
If at the time of exercise hereof there is no effective
registration statement registering, or the prospectus contained therein is not available for the issuance of the Warrant Shares to the
Holder, then this Warrant may also be converted, in whole or in part, into Common Stock at such time by means of a “cashless exercise”
in which the Holder shall deliver to the Company an executed Form of Election to Purchase and be entitled to receive a number
of Warrant Shares equal to the quotient obtained by dividing [(A-B) (X)] by (A), where:


 




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(A)
= as applicable: (i) the VWAP on the Trading Day immediately preceding the date of the applicable Form of Election to Purchase
if such Form of Election to Purchase is both executed and delivered pursuant to Section 4(a).


 


(B)
= the Exercise Price of this Warrant, as then in effect; and


 


(X)
= the number of Warrant Shares that would be issuable upon exercise of this Warrant in accordance with the terms of this Warrant
if such exercise were by means of a cash exercise rather than a cashless exercise.


 


Upon
receipt of the executed Form of Election to Purchase, the Company will confirm with the Holder the gross number of Warrants to be exercised
and the net number of Warrant Shares to be issued. The Company will promptly deliver to the Warrant Agent authorization to debit the
gross amount of Warrants and credit to the Holder the net amount of Warrant Shares.
If Warrant Shares are issued in such a cashless exercise, which is an exchange of the warrants for the Warrant Shares, the parties acknowledge
and agree that in accordance with Section 3(a)(9) of the Securities Act, the Warrant Shares shall take on the characteristics of the
Warrants being exercised. The Company agrees not to take any position contrary to this Section 4(f).


 


5.
Charges, Taxes and Expenses. Issuance
and delivery of certificates for Warrant Shares shall be made without charge to the Holder for any issue or transfer tax, or transfer
agent fee in respect of the issuance of such certificates, all of which taxes shall be paid by the Company; provided, however,
that the Company shall not be obligated to pay any tax which may be payable in respect of any transfer involved in the registration
of any certificates for Warrant Shares or Warrants in a name other than that of the Holder. The Holder shall be responsible for
all other tax liabilities that may arise as a result of holding or transferring any Warrant Certificate. The Company shall pay
all Warrant Agent and Transfer Agent fees required for same-day processing of any Form of Election to Purchase and all fees to
the Depository (or another established clearing corporation performing similar functions) required for same-day electronic delivery
of the Warrant Shares.


 


6.
Replacement of Warrant Certificate. If
any Warrant Certificate is mutilated, lost, stolen or destroyed, the Company shall issue or cause to be issued in exchange and
substitution for and upon cancellation thereof, or in lieu of and substitution for such Warrant Certificate, a New Warrant Certificate,
but only upon receipt of evidence reasonably satisfactory to the Company of such loss, theft or destruction and customary and
reasonable indemnity, if requested. Applicants for a New Warrant Certificate under such circumstances shall also comply with such
other reasonable regulations and procedures and pay such other reasonable third-party costs as the Company may prescribe.


 


7.
Reservation of Warrant Shares. The Company
covenants that it will at all times reserve and keep available out of its authorized but unissued and otherwise unreserved Common
Stock, solely for the purpose of enabling it to issue Warrant Shares upon exercise of all outstanding Warrants as herein provided,
the number of Warrant Shares which are then issuable and deliverable upon the exercise of all outstanding Warrants (taking into
account any adjustments pursuant to Section 8 below). The Company covenants that all Warrant Shares so issuable and deliverable
shall, upon issuance and the payment of the applicable Exercise Price in accordance with the terms hereof, be duly and validly
authorized and issued, and be fully paid and non-assessable.


 




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8.
Redemption of Warrants.


 


(a)
Beginning __________, 2021, [90 days from the
date of the Prospectus] outstanding Warrants may be redeemed at the option of the Company, in whole or in part on a pro-rata basis,
by giving not less than 30 days’ prior notice as provided in Section 8(c) below, which notice may not be given before, but
may be given at any time after the date on which the closing price of the Company’s common stock on the principal exchange
or trading facility on which it is then traded has equaled or exceeded $___ (175% of the public offering price of the Units) for
five consecutive Trading Days.


 


(b)
The price at which Warrants may be redeemed (the “Redemption
Price”) is $0.025 per Warrant. On and after the date upon which the Warrants are redeemed by the Company (the “Redemption
Date”), the Warrant Holders of redeemed Warrants shall be entitled to payment of the Redemption Price upon surrender of the
Warrant Certificates of such redeemed Warrants to the Warrant Agent (on behalf of the Company) at the office of the Warrant Agent.


 


(c)
Notice of redemption of Warrants shall be given
at least 30 days’ prior to the Redemption Date by the Company (i) notifying the Warrant Agent in writing of such redemption,
(ii) notifying the Warrant Holders of such redemption via publication of a press release and (iii)taking such other steps as may
be required under applicable law.


 


(d)
From and after the Redemption Date, all rights
of the Warrant Holders with respect to the redeemed Warrants (except the right to receive the Redemption Price) shall terminate,
but only if (i) no later than one day prior to the Redemption Date the Company shall have irrevocably deposited with the Warrant
Agent as paying agent a sufficient amount to pay on the Redemption Date the Redemption Price for all Warrants called for redemption
and (ii) the notice of redemption shall have stated the name and address of the Warrant Agent and the intention of the Company
to deposit such amount with the Warrant Agent no later than one day prior to the Redemption Date. Notwithstanding the foregoing,
the Company will extend a three-day “protect” period beginning on and continuing two days after the Redemption Date
so that any Warrant for which notice of exercise is received in the three business days prior to the Redemption Date shall be
deemed exercised so long as the Exercise Price is received by the Warrant Agent no more than three business days after the notice
of exercise is delivered to the Warrant Agent.


 


(e)
On the Redemption Date, the Warrant Agent shall
pay to the Warrant Holders of record of redeemed Warrants all monies received by the Warrant Agent for the redemption of Warrants
to which the Warrant Holders of record of such redeemed Warrants who shall have surrendered their Warrant Certificates are entitled.
The Warrant Agent shall have no obligation to pay for the redemption of Warrants except to the extent that funds for such payment
have been provided to it by the Company.


 




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(f)
All amounts deposited with the Warrant Agent
that are not required for redemption of Warrants may be withdrawn by the Company. Any amounts deposited with the Warrant Agent
that shall be unclaimed after six months after the Redemption Date shall be redelivered back to the Company, and thereafter the
Warrant Holders called for redemption for which such funds were deposited shall look solely to the Company for payment, it being
understood that the Warrant Agent shall be under no obligation to report or remit unclaimed property to appropriate states in
compliance with applicable law. The Company acknowledges that the bank accounts maintained by the Warrant Agent in connection
with the services hereunder will be in its name and that the Warrant Agent may receive investment earnings in connection with
the investment at the Warrant Agent’s risk and for its benefit of funds held in those accounts from time to time.


 


(g)
If the Company fails to make a sufficient deposit
with the Warrant Agent as provided above, the Warrant Holder called for redemption may at the option of the Warrant Holder (i)
by notice to the Company declare the notice of redemption a nullity as to such Warrant Holder, or (ii) maintain an action against
the Company for the Redemption Price. If the Warrant Holder brings such an action, the Company will pay reasonable attorneys’
fees of the holder. If the Warrant Holder fails to bring an action against the Company for the Redemption Price within 60 days
after the Redemption Date, the Warrant Holder shall be deemed to have elected to declare the notice of redemption to be a nullity
as to such Warrant Holder and such notice shall be without any force or effect as to such Warrant Holder. Except as otherwise
specifically provided in this Section 8(g), a notice of redemption, once published by the Company as provided in Section 8(c)
shall be irrevocable.


 


9.
Certain Adjustments. The Exercise Price
and number of Warrant Shares issuable upon exercise of each Warrant then outstanding are subject to adjustment from time to time
as set forth in this Section 9.


 


(a)
Stock Dividends and Splits. If the Company,
(i) pays a dividend or distribution in the form of shares of its Common Stock on its Common Stock, (ii) subdivides outstanding
shares of Common Stock into a greater number of shares or otherwise effects a stock split, or (iii) combines outstanding shares
of Common Stock into a lesser number of shares or otherwise effects a reverse split, then in each such case the Exercise Price
shall be multiplied by a fraction of which the numerator shall be the number of shares of Common Stock outstanding immediately
before such event and of which the denominator shall be the number of shares of Common Stock outstanding immediately after such
event. Any adjustment made pursuant to clause (i) of this subsection 9(a) shall become effective immediately after the record
date for the determination of stockholders entitled to receive such dividend or distribution, and any adjustment pursuant to clause
(ii) or (iii) of this paragraph shall become effective immediately after the effective date of such subdivision or combination.


 


(b)
Number of Warrant Shares. Simultaneously
with any adjustment to the Exercise Price pursuant to subsection 9(a) above, the number of Warrant Shares that may be purchased
upon exercise of each Warrant shall be increased or decreased proportionately, as the case may be, so that after such adjustment
the aggregate Exercise Price payable hereunder for the adjusted number of Warrant Shares shall be the same as the aggregate Exercise
Price in effect immediately prior to such adjustment.


 




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(c)
Certain Extraordinary Transactions. Except
as provided in Section 8(d), in case of any consolidation or merger of the Company into another corporation (other than a merger
in which the Company is the continuing corporation) or in case of any sale, lease or conveyance to another corporation of our
property as an entirety in which the proceeds of the transaction are distributed to the Company’s stockholders, the Company
shall, as a condition precedent to such transaction, cause effective provisions to be made so that the holder of the Warrants
shall have the right thereafter by exercising the Warrant, to purchase the kind and amount of shares of stock and other securities
and property receivable upon such consolidation, merger, sale or conveyance by a holder of the number of shares of Common Stock
which might have been purchased upon exercise of the warrant immediately prior to such consolidation, merger, sale or conveyance.
Any such provision shall include provision for adjustments which shall be as nearly equivalent as may be practicable to the adjustments
provided for in the warrant.


 


(d)
Notice of Adjustments. Upon the occurrence
of each adjustment pursuant to this Section 9, the Company at its expense will promptly calculate such adjustment in accordance
with the terms of this Agreement and prepare a certificate setting forth such adjustment, including a statement of the adjusted
Exercise Price and adjusted number of Warrant Shares or type of consideration issuable upon exercise of each Warrant (as applicable),
describing the transactions giving rise to such adjustments and showing in detail the facts upon which such adjustment is based.
The Company will reasonably promptly deliver or cause to be delivered to each Holder who makes a request in writing and to the
Warrant Agent, a copy of each such certificate.


 


(e)
Notice of Corporate Events. If the Company
(i) declares a dividend or any other distribution of cash, securities or other property in respect of its Common Stock (other
than a dividend payable solely in shares of Common Stock) or (ii) authorizes the voluntary dissolution, liquidation or winding
up of the affairs of the Company, or (iii) proposed a transaction involving a merger, consolidation, sale of assets or similar
transaction, including a proposed Specified Merger, then the Company shall deliver or cause to be delivered to each Holder a notice
describing the material terms and conditions of such dividend, distribution or transaction. Notwithstanding anything to the contrary
in this subsection 9(e), the failure to deliver any notice under this subsection 9(e) or any defect therein shall not affect the
validity of the corporate action required to be described in such notice. Until the exercise of a Holder’s Warrant or any
portion of such Warrant, a Holder shall not have nor exercise any rights by virtue of ownership of a Warrant as a stockholder
of the Company (including without limitation the right to notification of stockholder meetings or the right to receive any notice
or other communication concerning the business and affairs of the Company other than as provided in this subsection 9(e)), except
as expressly set forth in this Section 9.


 


(f)
Notices to Holders on Registration Statement.
If, at any time while any Warrants remain outstanding, the Registration Statement (or any subsequent registration statement registering
the sale or resale of the Warrant Shares) is not effective or is not otherwise available for the sale of the Warrant Shares, the
Company shall deliver notice to the record Holders that such registration statement is not then effective for the sale of Warrant
Shares and shall deliver notice to the record Holders if and when the registration statement is effective again and available
for the sale of the Warrant Shares (it being understood and agreed that the foregoing shall not limit the ability of any holder
thereof to sell any of the Warrant Shares in compliance with applicable federal and state securities laws). The Company shall
use its commercially reasonable best efforts to maintain a current and effective registration statement relating to the Warrant
Shares until the expiration of the Warrants.


 




    	10



    	 



    

 


(g)
To the extent that any notice provided to the
Holders under this Agreement constitutes, or contains, material, non-public information regarding the Company or any of the Company’s
subsidiaries, the Company shall simultaneously file such notice with the Commission on a Current Report on Form 8-K.


 


10.
Payment of Exercise Price. The Holder
shall pay the Aggregate Exercise Price by paying, in lawful money of the United States, by certified check payable to the Warrant
Agent, as agent for the Company, or bank draft payable to the order of the Company or by wire transfer of immediately available
funds to an account designated in writing by the Company (or as otherwise agreed to by the Company) delivered to the Warrant Agent
not later than one Trading Day after the Date of Exercise. Notwithstanding the foregoing, if payment is made in any form other
than a wire transfer of immediately available funds, neither the Warrant Agent nor the Company shall be required to issue Warrant
Shares until the Warrant Agent’s bank shall have confirmed that the payment has cleared, which date shall be the date that
the Holder has made payment of the Exercise Price.


 


11.
Holder Not Deemed a Stockholder. The Holder,
solely in such Person’s capacity as a Holder, shall not be entitled to vote or receive dividends or be deemed the holder
of shares of the Company for any purpose, nor shall anything contained in the Warrants be construed to confer upon the Holder,
solely in such Person’s capacity as a Holder of Warrants, any of the rights of a stockholder of the Company or any right
to vote, give or withhold consent to any corporate action (whether any reorganization, issue of stock, reclassification of stock,
consolidation, merger, conveyance or otherwise), receive notice of meetings, receive dividends or subscription rights, or otherwise,
prior to the issuance to the Holder of the Warrant Shares which such Person is then entitled to receive upon the due exercise
of the Warrants, except as expressly set forth in Section 8.


 


12.
No Fractional Shares. No fractional shares
will be issued in connection with any exercise of a Warrant. In lieu of any fractional shares which would otherwise be issuable,
the Company shall pay cash equal to the product of such fraction multiplied by the Exercise Price.


 


13.
Exchange Act Filings. The Holder agrees
and acknowledges that it shall have sole responsibility for making any applicable filings with the U.S. Securities and Exchange
Commission pursuant to Sections 13 and 16 of the Exchange Act as a result of its acquisition of any Warrant and the Warrant Shares
and any future retention or transfer thereof.


 


14.
Notices. Any and all notices or other
communications or deliveries hereunder (including without limitation any Form of Election to Purchase) shall be in writing and
shall be deemed given and effective on the earliest of (a) the date of transmission, if such notice or communication is delivered
via facsimile at the facsimile number or by PDF sent by email specified in this Section 14 prior to 5:00 p.m. (New York time)
on a Business Day, (b) the next Business Day after the date of transmission, if such notice or communication is delivered via
facsimile at the facsimile number or by PDF send by email as specified in this Section 14 on a day that is not a Business Day
or later than 5:00 p.m. (New York time) on any Business Day, (c) the Business Day following the date of mailing, if sent by nationally
recognized overnight courier service which provides evidence of delivery, or (d) upon actual receipt by the party to whom such
notice is required to be given. The addresses for such communications shall be:


 




    	11



    	 



    

 


if
to the Company:


 


Protagenic
Therapeutics, Inc.


149
Fifth Avenue


New
York, New York 10010


Attention:
Chief Financial Officer


Facsimile:
[_____]


Email:alex.arrow@protagenic.com


 


if
to the Warrant Agent:


 


American
Stock Transfer & Trust Company, LLC


6201
15th Avenue


Brooklyn,
NY 11219


Attention:
Warrant Department


Facsimile:
[_____]


Email:
[_____]


 


if
to the Holder:


 


to
the address or facsimile number or email appearing on the Warrant Register or such other address or facsimile number as the Holder
may provide to the Company in accordance with this Section 14.


 


15.
Warrant Agent.


 


(a)
The Company and the Warrant Agent hereby agree
that the Warrant Agent will serve as an agent of the Company as set forth in this Agreement.


 


(b)
The Warrant Agent shall not by any act hereunder
be deemed to make any representation as to validity or authorization of the Warrants or the Warrant Certificates (except as to
its countersignature thereon) or of any securities or other property delivered upon exercise of any Warrant, or as to the number
or kind or amount of securities or other property deliverable upon exercise of any Warrant or the correctness of the representations
of the Company made in such certificates that the Warrant Agent receives.


 


(c)
The Warrant Agent shall not have any duty to
calculate or determine any required adjustments with respect to the Exercise Price or the kind and amount of securities or other
property receivable by Holders upon the exercise of Warrants, nor to determine the accuracy or correctness of any such calculation.


 


(d)
The Warrant Agent shall not (i) be liable for
any recital or statement of fact contained herein or in the Warrant Certificates or for any action taken, suffered or omitted
by it in good faith in the belief that any Warrant Certificate or any other document or any signature is genuine or properly authorized,
(ii) be responsible for any failure by the Company to comply with any of its obligations contained in this Agreement or in the
Warrant Certificates, (iii) be liable for any act or omission in connection with this Agreement except for its own gross negligence
or willful misconduct or (iv) have any responsibility to determine whether a transfer of a Warrant complies with applicable securities
laws.


 




    	12



    	 



    

 


(e)
The Warrant Agent is hereby authorized to accept
instructions with respect to the performance of its duties hereunder solely on behalf of the Company from the Chief Executive
Officer, the President, the Chief Financial Officer, or the Secretary or any Assistant Secretary of the Company and to apply to
any such officer for written instructions (which will then be reasonably promptly given) and the Warrant Agent shall not be liable
for any action taken or suffered to be taken by it in good faith in accordance with the instructions of any such officer, except
for its own gross negligence or willful misconduct, but in its discretion the Warrant Agent may in lieu thereof accept other evidence
of such or may require such further or additional evidence as it may deem reasonable.


 


(f)
The Warrant Agent may exercise any of the rights
and powers hereby vested in it or perform any duty hereunder either itself or by or through its attorneys, agents or employees,
provided reasonable care has been exercised in the selection and in the continued employment of any persons. The Warrant Agent
shall not be under any obligation or duty to institute, appear in or defend any action, suit or legal proceeding in respect hereof,
unless first indemnified to its satisfaction. The Warrant Agent shall promptly notify the Company in writing of any claim made
or action, suit or proceeding instituted against or arising out of or in connection with this Agreement.


 


(g)
The Company will take such action as may reasonably
be required by the Warrant Agent in order to enable it to carry out or perform its duties under this Agreement.


 


(h)
The Warrant Agent shall act solely as agent of
the Company hereunder. The Warrant Agent shall only be liable for the failure to perform such duties as are specifically set forth
herein.


 


(i)
The Warrant Agent may, at its own expense, consult
with legal counsel satisfactory to it (who may be legal counsel for the Company), and the Warrant Agent shall incur no liability
or responsibility to the Company or to any Holder for any action taken, suffered or omitted by it in good faith in accordance
with the opinion or advice of such counsel.


 


(j)
The Company agrees to pay to the Warrant Agent
compensation for all services rendered by the Warrant Agent hereunder as the Company and the Warrant Agent may agree from time
to time, and to reimburse the Warrant Agent for reasonable expenses incurred in connection with the execution and administration
of this Agreement (including the reasonable compensation and expenses of its counsel), and further agrees to indemnify the Warrant
Agent for, and hold it harmless against, any loss, liability or expense incurred without gross negligence, bad faith or willful
misconduct on its part, arising out of or in connection with the acceptance and administration of this Agreement.


 




    	13



    	 



    

 


(k)
No resignation or removal of the Warrant Agent
and no appointment of a successor warrant agent shall become effective until the acceptance of appointment by the successor warrant
agent as provided herein. The Warrant Agent may resign its duties and be discharged from all further duties and liability hereunder
(except liability arising as a result of the Warrant Agent’s own gross negligence, bad faith or willful misconduct) after
giving 60 days prior written notice to the Company. The Company may remove the Warrant Agent upon written notice, and the Warrant
Agent shall thereupon in like manner be discharged from all further duties and liabilities hereunder, except as aforesaid. Upon
such resignation or removal, the Company shall appoint in writing a new warrant agent. If the Company fails to do so within a
period of 30 days after it has been notified in writing of such resignation by the resigning Warrant Agent or after such removal,
then the resigning Warrant Agent or the Holder of any Warrant (if such Holder first submits his, her or its Warrant Certificate
for inspection by the Company) may apply to any court of competent jurisdiction for the appointment of a new warrant agent, provided
that, for purposes of this Agreement, the Company shall be deemed to be the Warrant Agent until a new warrant agent is appointed.
After acceptance in writing of such appointment by the new warrant agent, it shall be vested with the same powers, rights, duties
and responsibilities as if it had been originally named herein as the Warrant Agent. Not later than the effective date of any
such appointment, the Company shall give notice thereof to the resigning or removed Warrant Agent. Failure to give any notice
provided for in this subsection 15(k), however, or any defect therein, shall not affect the legality or validity of the resignation
of the Warrant Agent or the appointment of a new warrant agent, as the case may be. The Company shall, or shall cause the successor
Warrant Agent to, deliver to each Holder at such Holder’s last address as shown on the register of Holders maintained by
the Warrant Agent, notice of the appointment of the successor Warrant Agent and such successor Warrant Agent’s address for
communication.


 


(l)
Any corporation into which the Warrant Agent
or any new warrant agent may be merged or converted or any corporation resulting from any consolidation to which the Warrant Agent
or any new warrant agent shall be a party or any corporation to which the Warrant Agent transfers substantially all of its corporate
trust business shall be a successor Warrant Agent under this Agreement without any further act, provided that such corporation
(i) would be eligible for appointment as successor to the Warrant Agent under the provisions of subsection 15(k) above or (ii)
is a wholly owned subsidiary of the Warrant Agent. Any such successor Warrant Agent shall promptly cause notice of its succession
as Warrant Agent to be mailed (by first class mail, postage prepaid) to each Holder in accordance with Section 14 above.


 


16.
Miscellaneous.


 


(a)
Successors and Assigns. This Agreement
shall be binding on and inure to the benefit of the Company, the Warrant Agent and the Holders, and their respective successors
and assigns. Subject to the preceding sentence, nothing in this Agreement shall be construed to give to any Person other than
the Company, the Warrant Agent and the Holders any legal or equitable right, remedy or cause of action under this Agreement.


 




    	14



    	 



    

 


(b)
Amendments and Waivers. The Company may,
without the consent of the Holders, by supplemental agreement or otherwise, add to the covenants and agreements of the Company
for the benefit of the Holders, or surrender any rights or power reserved to or conferred upon the Company in this Agreement,
provided that such changes or corrections shall not adversely affect the interests of Holders of then outstanding Warrants in
any respect. The Company may, with the consent, in writing or at a meeting, of the Holders of outstanding Warrants exercisable
for a majority of the Warrant Shares, amend in any way, by supplemental agreement or otherwise, this Agreement and/or all of the
outstanding Warrant Certificates; provided, however, that no such amendment shall adversely affect any Warrant differently than
it affects all other Warrants, unless the Holder thereof consents thereto. The Warrant Agent shall, at the request of the Company,
and without need of independent inquiry as to whether such supplemental agreement is permitted by the terms of this Section 16(b),
join with the Company in the execution and delivery of any such supplemental agreements, but shall not be required to join in
such execution and delivery for such supplemental agreement to become effective.


 


(c)
Choice of Law, etc. All questions concerning
the construction, validity, enforcement and interpretation of this Agreement shall be governed by and construed and enforced in
accordance with the internal laws of the State of New York, without regard to the principles of conflicts of law thereof. Each
party hereto hereby irrevocably waives, to the fullest extent permitted by applicable law, any and all right to trial by jury
in any legal proceeding arising out of or relating to this Agreement or the transactions contemplated hereby. If either party
shall commence an action or proceeding to enforce any provisions of this Agreement, then the prevailing party in such action or
proceeding shall be reimbursed by the other party for its attorneys’ fees and other costs and expenses incurred with the
investigation, preparation and prosecution of such action or proceeding.


 


(d)
Interpretation. The headings herein are
for convenience only, do not constitute a part of this Agreement and shall not be deemed to limit or affect any of the provisions
hereof.


 


(e)
Severability. In case any one or more
of the provisions of this Agreement shall be invalid or unenforceable in any respect, the validity and enforceability of the remaining
terms and provisions of this Agreement shall not in any way be affected or impaired thereby and the parties will attempt in good
faith to agree upon a valid and enforceable provision which shall be a commercially reasonable substitute therefor, and upon so
agreeing, shall incorporate such substitute provision in this Agreement.


 


(f)
Execution. This Agreement may be executed
in counterparts, all of which when taken together shall be considered one and the same agreement and shall become effective when
counterparts have been signed by each party and delivered to each other party, it being understood that the parties need not sign
the same counterpart. In the event that any signature is delivered by facsimile or electronic transmission or by e-mail delivery
of a “.pdf” format data file, such signature shall create a valid and binding obligation of the party executing (or
on whose behalf such signature is executed) with the same force and effect as if such facsimile or “.pdf” signature
page were an original thereof.


 


(g)
Additional Warrants. The Company may from
time to time issue additional warrants (the “Additional Warrants”) under this Agreement, without requiring
the consent of any Holder, with the same terms as the warrants initially issued hereunder.


 


[The
remainder of this page has been left intentionally blank.]


 




    	15



    	 



    

 





IN
WITNESS WHEREOF, the undersigned has caused this Agreement to be duly executed by its authorized officer as of the date first
indicated above.


 


	 	PROTAGENIC
    THERAPEUTICS, INC.
	 	 	 
	 	By:	                 
	 	Name:	 
	 	Title:	 


 


[Company
Signature Page to Warrant Agent Agreement]


 




    	 



    	 



    

 





IN
WITNESS WHEREOF, the undersigned has caused this Agreement to be duly executed by its authorized officer as of the date first
indicated above.


 


	 	AMERICAN
    STOCK TRANSFER & TRUST COMPANY, LLC,
	 	as
    Warrant Agent
	 	 	 
	 	By:	       
	 	Name:	 
	 	Title:	 


 


[Warrant
Agent Signature Page to Warrant Agent Agreement]


 




    	 



    	 



    

 


Exhibit
A


 


[UNLESS
THIS GLOBAL WARRANT CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION
(“DTC”), TO THE COMPANY OR ITS AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE OR PAYMENT, AND ANY CERTIFICATE ISSUED
IS REGISTERED IN THE NAME OF CEDE & CO. OR SUCH OTHER NAME AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC (AND ANY
PAYMENT IS MADE TO CEDE & CO., OR TO SUCH OTHER ENTITY AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC), ANY TRANSFER,
PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL INASMUCH AS THE REGISTERED OWNER HEREOF, CEDE&
CO., HAS AN INTEREST HEREIN.


 


TRANSFERS
OF THIS GLOBAL SECURITY SHALL BE LIMITED TO TRANSFERS IN WHOLE, BUT NOT IN PART, TO NOMINEES OF DTC OR TO A SUCCESSOR THEREOF
OR SUCH SUCCESSOR’S NOMINEE AND TRANSFERS OF PORTIONS OF THIS GLOBAL SECURITY SHALL BE LIMITED TO TRANSFERS MADE IN ACCORDANCE
WITH THE RESTRICTIONS SET FORTH IN THE WARRANT AGENT AGREEMENT.


 


ANY
TRANSFER OF THE SECURITIES REPRESENTED BY THIS GLOBAL WARRANT CERTIFICATE IS SUBJECT TO THE CONDITIONS SPECIFIED IN THE WARRANT
AGENT AGREEMENT (THE “WARRANT AGREEMENT”) DATED AS OF APRIL [ ], 2021 BETWEEN PROTAGENIC THERAPEUTICS, INC. AND AMERICAN
STOCK TRANSFER & TRUST COMPANY, LLC, SOLELY IN ITS CAPACITY AS WARRANT AGENT. BY ACCEPTING DELIVERY OF THE SECURITIES REPRESENTED
BY THIS GLOBAL WARRANT CERTIFICATE, ANY TRANSFEREE SHALL BE DEEMED TO HAVE AGREED TO BE BOUND BY THE WARRANT AGREEMENT AS IF THE
TRANSFEREE HAD EXECUTED AND DELIVERED THE WARRANT AGREEMENT.]


 


EXERCISABLE
ON OR AFTER APRIL [  ], 2021

AND UNTIL 5:00 P.M. (NEW YORK TIME) ON THE EXPIRATION DATE


 


	CUSIP:	 	 	 
	No.	 	 	Warrants
    to Purchase [____________] Shares


 


Warrant
Certificate


 


WARRANTS
TO PURCHASE COMMON STOCK OF 


 


PROTAGENIC
THERAPEUTICS, INC.


 


This
Warrant Certificate certifies that [______________], or registered assigns, is the registered holder of Warrants (the “Warrants”)
to acquire from Protagenic Therapeutics, Inc., a Delaware corporation (the “Company”), the aggregate number
of fully paid and non-assessable shares of common stock of the Company, par value $0.000001 per share (the “Common
Stock”), specified above for consideration equal to the Exercise Price (as defined in the Warrant Agreement (as defined
below)) per share of Common Stock. The Exercise Price and number of shares of Common Stock and/or type of securities or property
issuable upon exercise of the Warrants are subject to adjustment upon the occurrence of certain events as set forth in the Warrant
Agreement. The Warrants evidenced by this Warrant Certificate shall not be exercisable after and shall terminate and become void
as of 5:00 P.M., New York time, on [  ], 2026 (the “Expiration Date”).


 




    	 



    	 



    

 


The
Warrants evidenced by this Warrant Certificate are part of a duly authorized issue of warrants expiring on the Expiration Date
entitling the Holder hereof to receive shares of Common Stock, and is issued or to be issued pursuant to a Warrant Agent Agreement,
dated April [  ], 2021 (the “Warrant Agreement”), duly executed and delivered by the Company and American Stock
Transfer & Trust Company, LLC, as warrant agent (the “Warrant Agent,” which term includes any successor
warrant agent under the Warrant Agreement), which Warrant Agreement is hereby incorporated by reference in and made a part of
this instrument and is hereby referred to for a description of the rights, limitation of rights, obligations, duties and immunities
thereunder of the Warrant Agent, the Company and the Holders (“Holders” meaning, from time to time, the registered
holders of the warrants issued thereunder). To the extent any provisions of this Warrant Certificate conflicts with any provision
of the Warrant Agreement, the provisions of the Warrant Agreement shall apply. A copy of the Warrant Agreement may be obtained
by the Holder hereof upon written request to the Company at Protagenic Therapeutics, Inc., Attn: Chief Financial Officer. Capitalized
terms not defined herein have the meanings ascribed thereto in the Warrant Agreement.


 


The
Warrants evidenced by this Warrant Certificate may be exercised, in whole or in part, at any time on or after April [ ], 2021
and on or before the Expiration Date, in the manner and subject to the terms of the Warrant Agreement including, but not limited
to, Sections 4 and 8 thereof. Each exercise must be for a whole number of Warrant Shares.


 


The
Warrant Agreement provides that upon the occurrence of certain events the Exercise Price set forth in this Warrant Certificate
may, subject to certain conditions, be adjusted, and that upon the occurrence of certain events the number of shares of Common
Stock and/or the type of securities or other property issuable upon the exercise of the Warrants evidenced by this Warrant Certificate
shall be adjusted. The Warrant Agreement also provides for the automatic conversion of the Warrants under certain circumstances.
No fractional share of Common Stock will be issued upon the exercise of the Warrants evidenced by this Warrant Certificate, but
the Company will at its election either pay the cash value thereof determined as provided in the Warrant Agreement or round the
fractional share to the next whole share.


 


Warrant
Certificates, when surrendered at the office of the Warrant Agent by the registered Holder thereof in person or by such Holder’s
legal representative or attorney duly appointed and authorized in writing, may be exchanged, in the manner and subject to the
limitations provided in the Warrant Agreement, but without payment of any service charge, for another Warrant Certificate or Warrant
Certificates of like tenor evidencing in the aggregate the right to purchase a like number of Warrant Shares.


 


Each
taker and holder of this Warrant Certificate, by taking or holding the same, consents and agrees that the holder of this Warrant
Certificate when duly endorsed in blank may be treated by the Company, the Warrant Agent and all other persons dealing with this
Warrant Certificate as the absolute owner hereof for any purpose and as the person entitled to exercise the rights represented
hereby or the person entitled to the transfer hereof on the register of the Company maintained by the Warrant Agent, any notice
to the contrary notwithstanding, provided that until such transfer on such register, the Company and the Warrant Agent may treat
the registered Holder hereof as the owner for all purposes.


 


The
Warrants evidenced by this Warrant Certificate do not entitle any Holder to any of the rights of a stockholder of the Company.


 


This
Warrant Certificate and the Warrant Agreement are subject to amendment as provided in the Warrant Agreement.


 


This
Warrant Certificate shall not be valid or obligatory for any purpose until it shall have been countersigned by the Warrant Agent.


 


[The
remainder of this page has been left intentionally blank.]


 




    	2



    	 



    

 


IN
WITNESS WHEREOF, the undersigned have caused this Global Warrant Certificate to be executed as of the date set forth below.


 


	 	PROTAGENIC
    THERAPEUTICS, INC.
	 	 	 
	 	By:	               
	 	Name:	 
	 	Title:	 


 


	Dated:	 
	 	 
	 	 
	Countersigned:	 
	AMERICAN
    STOCK TRANSFER & TRUST	 
	COMPANY,
    LLC,	 
	as
    Warrant Agent	 


 


	By:	 	 
	Name:	 	 
	Title:	 	 


 


[Signature
page to [Global] Warrant Certificate]


 




    	 



    	 



    

 


FORM
OF ASSIGNMENT


 


[To
be completed and signed only upon transfer of Warrant]


 


FOR
VALUE RECEIVED, the undersigned hereby sells, assigns and transfers unto _______________________________________ the right represented
by the within Warrant Certificate to purchase ______________ shares of common stock of Protagenic Therapeutics, Inc. to which
the within Warrant Certificate relates and appoints _______________________________ attorney to transfer said right on the books
of Protagenic Therapeutics, Inc. with full power of substitution in the premises.


 


Dated:
___________________


 


_______________________________________________________________________________________________





Printed
Name of Holder


 





_______________________________________________________________________________________________


Signature
of Holder (signature must conform in all respects to name of holder as specified on the front page of the Warrant Certificate)


 


_______________________________________________________________________________________________


Title
of Signatory (if Holder is not a natural person)


 


Address
of Transferee:


_______________________________________________________________________________________________


_______________________________________________________________________________________________


_______________________________________________________________________________________________


_______________________________________________________________________________________________


 





Signature
Guaranteed By:


 


______________________


 





The
signature to this Form of Assignment must correspond with the name as it appears on the face of the Warrant Certificate in every
particular. Officers signing on behalf of a corporation, partnership, trust or other entity must provide evidence of authority
to assign the foregoing Warrant upon request of the Company or Warrant Agent. The signature must be guaranteed by a U.S. chartered
bank or by a medallion signature guarantee from a member of a recognized Signature Medallion Guarantee Program.


 




    	 



    	 



    

 


FORM
OF ELECTION TO PURCHASE


 


To
Protagenic Therapeutics, Inc.:


 


In
accordance with [Warrant Certificate No. enclosed with this Form of Election to Purchase][the Global Warrant Certificate to be
delivered in connection with this Form of Election to Purchase in the manner contemplated by the Warrant Agreement (as defined
below)], the undersigned hereby irrevocably elects to exercise the Warrants evidenced by this Warrant Certificate with respect
to Warrant Shares in accordance with the terms of the Warrant Agent Agreement dated April [  ], 2021, between Protagenic Therapeutics,
Inc., a Delaware corporation, and American Stock Transfer & Trust Company, LLC, as warrant agent (the “Warrant Agreement”).
Terms used and not defined herein have the meanings specified in the Warrant Agreement.


 


The
Holder hereby agrees to pay the Aggregate Exercise Price, in lawful money of the United States, by certified check payable to
the Warrant Agent, as agent for the Company, or bank draft payable to the order of the Company or by wire transfer of immediately
available funds to an account designated in writing by the Company (or as otherwise agreed to by the Company) delivered to the
Warrant Agent, together with any applicable taxes payable by the undersigned pursuant to the terms of the Warrant Agreement.


 


Unless
the Warrant Shares will be delivered electronically via DWAC, the undersigned requests that certificates for the shares of Common
Stock issuable upon this exercise be issued in the name of:


 


Name:
     _______________________________


Address:
 _______________________________


 
               _______________________________


 


Social
Security or Tax I.D. No.: _______________


 


If
the Warrant Shares will be delivered electronically via DWAC, the undersigned requests that the Warrant Shares issuable upon this
exercise be issued to the following account:


 


	Name
    of DTC Participant:	 
	 	 
	DTC
    Participant Number:	 
	 	 
	Name
    of Account at DTC Participant to be credited with the Warrant Shares:	 
	 	 
	Account
    Number at DTC Participant to be credited with the Warrant Shares:	 
	 	 


 


This
Election to Purchase is delivered by:


 


_______________________________________________________________________________________________


Signature
(and title, if applicable) of Authorized Signatory of Holder


 


_______________________________________________________________________________________________


Name
of Holder


 


_______________________________________________________________________________________________


Date


 




    	2



    	 



    

 


Warrant
Shares Exercise Log


 


	Date	 	Number
    of Warrant Shares Available to be Exercised	 	 	Number
    of Warrant Shares Exercised	 	 	Number
    of Warrant Shares Remaining to be Exercised