<PAGE>   1
                                                                    EXHIBIT 3.A
                                    RESTATED

                          CERTIFICATE OF INCORPORATION

                                       OF

                         EL PASO TENNESSEE PIPELINE CO.

         EL PASO TENNESSEE PIPELINE CO., a corporation organized and existing
under the laws of the State of Delaware, hereby certifies as follows:

         1.       The name of the corporation is El Paso Tennessee Pipeline Co.
                  (the "Corporation"). The Corporation was incorporated under
                  the name Tenneco Holdings, Inc., on October 7, 1987, which
                  name was changed to Tenneco Inc., on December 8, 1987, and to
                  El Paso Tennessee Pipeline Co., on December 11, 1996. The
                  original certificate of incorporation was filed with the
                  Secretary of State of the State of Delaware on October 7,
                  1987.

         2.       This Restated Certificate of Incorporation restates but does
                  not further amend the Certificate of Incorporation as
                  heretofore amended, of the Corporation and has been adopted
                  and approved in accordance with Section 245 of the General
                  Corporation Law of the State of Delaware.

         3.       The text of the Certificate of Incorporation, as heretofore
                  amended, is hereby restated to read in its entirety as
                  follows:

         FIRST:  The name of the Corporation is El Paso Tennessee Pipeline Co.

         SECOND: The address of its registered office in the State of Delaware
is Corporation Trust Center, 1209 Orange Street, in the City of Wilmington,
County of New Castle. The name of its registered agent at such address is The
Corporation Trust Company.

         THIRD: The purpose of the Corporation is to engage in any lawful act
or activity for which corporations may be organized under the General
Corporation Law of the State of Delaware.

         FOURTH: The total number of shares of all classes of stock which the
Corporation shall be authorized to issue is 20,000,000 shares of Preferred
Stock, par value $.01 per share (herein called "Preferred Stock"), and 100,000
shares of Common Stock, of the par value of $.01 per share (herein called
"Common Stock").

                                      -1-

<PAGE>   2


                                       I.

         1. The Board of Directors of the Corporation is hereby expressly
authorized, by resolution or resolutions thereof, to provide, out of the
unissued shares of Preferred Stock, for series of Preferred Stock and, with
respect to each such series, to fix the number of shares constituting such
series and the designation of such series, the voting powers (if any) of the
shares of such series, and the preferences and relative, participating,
optional or other special rights, if any, and any qualifications, limitations
or restrictions thereof, of the shares of such series. The powers, preferences
and relative, participating, optional and other special rights of each series
of Preferred Stock, and the qualifications, limitations or restrictions
thereof, if any, may differ from those of any and all other series at any time
outstanding.

         2. Except as otherwise provided in any resolution of the Board of
Directors providing for the issuance of any particular series of Preferred
Stock, shares of Preferred Stock redeemed or otherwise acquired by the
Corporation shall, upon the filing of any required certificates with the
Secretary of State of Delaware, assume the status of authorized but unissued
Preferred Stock and may thereafter, subject to the provisions of this Part I of
Article FOURTH and of any restrictions contained in any resolution of the Board
of Directors providing for the issue of any particular series of Preferred
Stock, be reissued in the same manner as other authorized but unissued
Preferred Stock.

     Preferred Stock Designated 8 1/4% Cumulative Preferred Stock, Series A

         Pursuant to the authority vested in the Board of Directors of the
Corporation by the Certificate of Incorporation, as amended (as such may be
amended from time to time, the "Certificate of Incorporation") and authority
vested by such Board of Directors in a Preferred Stock Issuance Committee, all
of the members of which are members of the Board of Directors, a series of
Preferred Stock of the Corporation be, and hereby is, created to be designated
"8 1/4% Cumulative Preferred Stock, Series A" (hereinafter referred to as the
"Series A Preferred Stock"), consisting of 6,000,000 shares, and the
designations, powers, preferences and relative and other special rights and the
qualifications, limitations and restrictions of the Series A Preferred Stock
are hereby fixed and stated to be as follows (all terms used herein which are
defined in the Certificate of Incorporation shall be deemed to have the
meanings provided therein):

         Section 1. Dividends. (a) The dividend rate on the Series A Preferred
     Stock shall be 8 1/4% of $50 per share of Series A Preferred Stock per
     annum (2.0625% per quarter annum). Dividends (including Additional DRD
     Dividends (as defined in Section 2)) on shares of the Series A Preferred
     Stock shall accrue, whether or not declared, on a daily basis from the
     date of issuance of such shares. Accrued but unpaid dividends shall not
     bear interest.

         (b) Dividends on the Series A Preferred Stock shall be payable, when,
     as and if declared by the Board of Directors of the Corporation out of
     assets legally available therefor, quarter-yearly on the last days of
     March, June, September and December in each 

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<PAGE>   3

     year (each, a "Dividend Payment Date"), with the first dividend payment 
     date being the next Dividend Payment Date following the date of issuance. 
     Dividends on each Dividend Payment Date will be payable to holders of 
     record of the Series A Preferred Stock as they appear on the stock books 
     of the Corporation on a record date, not more than 60 days preceding such 
     Dividend Payment Date, fixed for such purpose by the Board of Directors in
     advance of such Dividend Payment Date. Dividends payable on the Series A 
     Preferred Stock for any period shorter than a quarter-yearly dividend 
     period shall be computed on the basis of a 360-day year of twelve 30-day 
     months. The Series A Preferred Stock shall rank on a parity with each 
     other series of Preferred Stock as to the payment of dividends, except to 
     the extent otherwise provided in Section 7 hereof or in the resolution or 
     resolutions providing for the issuance of such other series.

         (c) If (x) the Stock Issuance (as defined in the Amended and Restated
     Agreement and Plan of Merger, dated as of June 19, 1996, as such may be
     amended or supplemental from time to time (the "Merger Agreement") among
     the Corporation, El Paso Natural Gas Company, a Delaware corporation ("El
     Paso") and El Paso Merger Company, a Delaware corporation) is not approved
     by the stockholders of El Paso at a special meeting of El Paso
     stockholders (including any adjournments or postponements thereof, the "El
     Paso Special Meeting") called to approve such issuance, (y) the Merger (as
     defined in the Merger Agreement) is effected, and (z) on or before the
     90th day after the date of the El Paso Special Meeting, either Standard &
     Poor's Corp. ("S&P") or Moody's Investors Service, Inc. ("Moody's")
     downgrades the rating previously given by it to the Series A Preferred
     Stock, the annual dividend rate set forth in (a) above will be
     automatically subjected to a one-time upward adjustment to the rate set
     forth in the table below opposite the applicable ratings which are given
     to the Series A Preferred Stock by each of Moody's and S&P as of the 90th
     day after the El Paso Special Meeting, effective as of the date of
     original issuance of the Series A Preferred Stock.

<TABLE>
<CAPTION>

                                                              ANNUAL
                                                             DIVIDEND
              REVISED RATINGS (MOODY'S/S&P)                    RATE
              -----------------------------                  --------
<S>                                                        <C>   
              Ba1/BB+ ................................        9.000%
              Ba2/BB+ or Ba1/BB ......................        9.125%
              Ba2/BB .................................        9.250%
              Ba3/BB or Ba2/BB- ......................        9.500%
              Ba3/BB- ................................       10.000%
</TABLE>

         If any such adjustment to the annual dividend rate occurs after a
     Dividend Payment Date as to which the Corporation previously paid dividends
     on the Series A Preferred Stock, additional dividends will be payable, out
     of funds legally available therefor, on each share of Series A Preferred
     Stock on the next succeeding Dividend Payment Date (or if such adjustment
     occurs after the dividend payable on the next succeeding Dividend Payment
     Date has been declared, on the second succeeding Dividend Payment Date
     following the date of such adjustment) to the holder of record of such
     share of Series A Preferred Stock as of the record date established for
     such succeeding Dividend Payment 

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<PAGE>   4
     Date (or second succeeding Dividend Payment Date, as the case may be) in an
     amount equal to the excess of (x) the aggregate amount of dividends that
     would have been payable on such share on all Dividend Payment Dates as to
     which the Corporation previously paid dividends on the Series A Preferred
     Stock if dividends had accrued from the date of issuance of the Series A
     Preferred Stock at the adjusted annual dividend rate, over (y) the
     aggregate amount of dividends actually paid with respect to such share of
     Series A Preferred Stock. If the annual dividend rate is adjusted as
     provided above, the Corporation will cause notice of such adjustment to be
     sent to the holders of record of the Series A Preferred Stock as they
     appear in the stock register of the Corporation.

         Section 2. Changes in the Dividends Received Percentage. (a)
     Notwithstanding Section 1 hereof, if one or more amendments to the
     Internal Revenue Code of 1986, as amended (the "Code"), are enacted that
     reduce the percentage of the dividends received deduction as specified in
     Section 243(a)(1) of the Code or any successor provision (the "Dividends
     Received Percentage") to below 70%, the amount of each dividend payable
     per share of the Series A Preferred Stock for dividend payments made on or
     after the effective date of such change (or the second succeeding dividend
     payment after such effective date, as herein described) will be adjusted
     by multiplying the amount of the dividend payable pursuant to Section 1
     (before adjustment pursuant to this Section 2) by a factor, which will be
     the number determined in accordance with the following formula (the "DRD
     Formula"), and rounding the result to the nearest cent:

                              1 - (.35(1 - .70))
                              ------------------
                              1 - (.35(1 - DRP))

         For the purposes of the DRD Formula, "DRP" means the Dividends
     Received Percentage applicable to the dividend in question. No amendments
     to the Code, other than a change in the percentage of the dividends
     received deduction set forth in Section 243 (a)(1) of the Code or any
     successor provision, will give rise to an adjustment. Notwithstanding the
     foregoing provisions of this Section 2, in the event that, with respect to
     any such amendment, the Corporation receives either an unqualified opinion
     of nationally recognized independent tax counsel selected by the
     Corporation or a private letter ruling or similar form of authorization
     from the Internal Revenue Service to the effect that such an amendment
     would not apply to dividends payable on the Series A Preferred Stock, then
     any such amendment will not result in the adjustment provided for pursuant
     to the DRD Formula. The opinion referenced in the previous sentence must
     be based upon a specific exception in the legislation amending the DRP or
     upon a published pronouncement of the Internal Revenue Service addressing
     such legislation. The Corporation's calculation of the dividends payable,
     as so adjusted and as certified accurate as to calculation and reasonable
     as to method by the independent public accountants then regularly engaged
     by the Corporation, will be final and not subject to review absent
     manifest error.

         (b) If any amendment to the Code which reduces the Dividends Received
     Percentage to below 70% is enacted after a dividend payable on Dividend
     Payment Date has been declared but prior to the applicable Dividend
     Payment Date, the amount of dividend 

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<PAGE>   5

     payable on such Dividend Payment Date will not be increased. Instead,
     an amount, equal to the excess of (x) the product of the dividends
     paid by the Corporation on such Dividend Payment Date and the factor
     derived from the DRD Formula (where the DRP used in the DRD Formula
     would be equal to the reduced Dividends Received Percentage for such
     dividends), over (y) the dividends paid by the Corporation on such
     Dividend Payment Date, will be payable, out of funds legally available
     therefor, to holders of record as of the record date established for
     the next succeeding Dividend Payment Date in addition to any other
     amounts payable on such date. Notwithstanding the foregoing, no such
     additional dividend will be payable pursuant to this Section 2 if the
     such amendment to the Code would not result in an adjustment to the
     DRD Formula due to the Corporation having received either an opinion
     of counsel or tax ruling referred to in paragraph (a) of this Section 2.

         (c) If, prior to March 31, 1997, an amendment to the Code is enacted
     that reduces the Dividends Received Percentage to below 70% and such
     reduction retroactively applies to a Dividend Payment Date as to which the
     Corporation previously paid dividends on the Series A Preferred Stock
     (each an "Affected Dividend Payment Date"), additional dividends (the
     "Additional DRD Dividends") will be payable out of funds legally available
     therefor on the next succeeding Dividend Payment Date (or if such
     amendment is enacted after the dividend payable on such Dividend Payment
     Date has been declared, on the second succeeding Dividend Payment Date
     following the date of enactment) to holders of record as of the record
     date established for such succeeding Dividend Payment Date (or second
     succeeding Dividend Payment Date, as the case my be) in an amount equal to
     the excess of (x) the product of the dividends paid by the Corporation on
     each Affected Dividend Payment Date and the factor derived from the DRD
     Formula (where the DRP used in the DRD Formula would be equal to the
     reduced Dividends Received Percentage applied to each Affected Dividend
     Payment Date), over (y) the dividends paid by the Corporation on all
     Affected Dividend Payment Dates.

         (d) Additional DRD Dividends will not be payable in respect of the
     enactment of any amendment to the Code on or after March 31, 1997 which
     retroactively reduces the Dividends Received Percentage to below 70%, or
     if enacted prior to March 31, 1997, which would not result in an
     adjustment due to the Corporation having received either an opinion of
     counsel or tax ruling referred to in paragraph (a) of this Section 2. The
     Corporation shall only be required to make one payment of Additional DRD
     Dividends.

         (e) In the event that the amount of dividends payable per share of the
     Series A Preferred Stock are adjusted pursuant to the DRD Formula and/or
     Additional DRD Dividends are to be paid, the Corporation shall cause
     notice of each such adjustment and, if applicable, any Additional DRD
     Dividends to be sent to the holders of record of the Series A Preferred
     Stock as they appear in the stock register of the Corporation.

         Section 3. Optional Redemption. (a) At any time or from time to time,
     on or after December 31, 2001, the Series A Preferred Stock may be
     redeemed at the option of the Corporation, in whole or in part, out of
     funds legally available therefor, at a redemption 

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<PAGE>   6

     price equal to $50.00 per share plus an amount equal to accrued and
     unpaid dividends (whether or not declared) to but excluding the date
     fixed for redemption including any changes in dividends payable due to
     changes in the annual dividend rate or Dividends Received Percentage,
     and Additional DRD Dividends, if any. In addition to any restrictions
     or limitations contained in the Certificate of Incorporation, if any,
     if full cumulative dividends on the Series A Preferred Stock for all
     past dividend periods have not been paid or declared and set apart for
     payment, the Series A Preferred Stock may be redeemed only in full
     (but not in part) by the Corporation pursuant to this paragraph (a)
     and the Corporation shall not purchase or acquire any shares of Series
     A Preferred Stock other than pursuant to Section 4 hereof or pursuant
     to a purchase or exchange offer made on the same terms to all holders
     of the Series A Preferred Stock. If fewer than all the outstanding
     shares of Series A Preferred Stock are to be redeemed, the Corporation
     will select those to be redeemed pro rata, by lot or by a
     substantially equivalent method.

         (b) If the Dividends Received Percentage is equal to or less than 40%
     and, as a result, the amount of dividends on the Series A Preferred Stock
     payable on any Dividend Payment Date will be or is adjusted upwards as
     provided in Section 2, the Corporation, at its option, may redeem all, but
     not less than all, of the outstanding shares of the Series A Preferred
     Stock, out of funds legally available therefor, provided that within 60
     days of the date on which an amendment to the Code is enacted which
     reduces the Dividends Received Percentage to 40% or less, the Corporation
     gives notice of redemption as provided in paragraph (d) of this Section 3
     to all holders of record of the Series A Preferred Stock. A redemption of
     the Series A Preferred Stock in accordance with this paragraph (b) shall
     be at the applicable redemption price set forth in the following table, in
     each case plus an amount equal to accrued and unpaid dividends (whether or
     not declared) thereon to but excluding the date fixed for redemption,
     including any changes in dividends payable due to changes in the annual
     dividend rate or Dividends Received Percentage, and Additional DRD
     Dividends, if any:

<TABLE>
<CAPTION>
                                                                  REDEMPTION
                                                                   PRICE PER
      REDEMPTION PERIOD                                              SHARE
      -----------------                                           ----------
<S>                                                                <C>      
      November 18, 1996 to December 30, 1997 ...................   $   52.50
      December 31, 1997 to December 30, 1998 ...................       52.00
      December 31, 1998 to December 30, 1999 ...................       51.50
      December 31, 1999 to December 30, 2000 ...................       51.00
      December 31, 2000 to December 30, 2001 ...................       50.50
      December 31, 2001 and thereafter .........................       50.00
</TABLE>

         (c) If at any time fewer than 600,000 shares of Series A Preferred
     Stock remain outstanding, the Corporation, at its option, may redeem all,
     but not less than all, of the outstanding Series A Preferred Stock. A
     redemption of the Series A Preferred Stock in accordance with this
     paragraph (c) shall be at the applicable redemption price set forth in the
     following table, in each case plus an amount equal to accrued but unpaid
     dividends (whether or not declared) thereon to but excluding the date
     fixed for redemption, including 

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<PAGE>   7

     any changes in dividends payable due to changes in the annual dividend 
     rate or the Dividends Received Percentage, and Additional DRD Dividends, 
     if any:

<TABLE>
<CAPTION>
                                                                   REDEMPTION
                                                                    PRICE PER
      REDEMPTION PERIOD                                              SHARE
      -----------------                                            ----------
<S>                                                                <C>      
      November 18, 1996 to December 30, 1997 ...................   $   52.50
      December 31, 1997 to December 30, 1998 ...................   $   52.00
      December 31, 1998 to December 30, 1999 ...................   $   51.50
      December 31, 1999 to December 30, 2000 ...................   $   51.00
      December 31, 2000 to December 30, 2001 ...................   $   50.50
      December 31, 2001 and thereafter .........................   $   50.00
</TABLE>

         (d) Notice of redemption pursuant to paragraph (a), (b) or (c) of this
     Section 3 will be given by mail, (i) not less than 30 days prior to the
     date fixed for redemption thereof in the case of paragraph (a) and (ii)
     not less than 30 nor more than 60 days prior to the date fixed for
     redemption thereof, in the case of paragraphs (b) and (c), in each case to
     each record holder of the shares of Series A Preferred Stock to be
     redeemed at the address of such holder in the stock register of the
     Corporation. If a notice of redemption has been given, from and after the
     specified redemption date (unless the Corporation defaults in making
     payment of the redemption price), dividends on the Series A Preferred
     Stock so called for redemption will cease to accrue, such shares will no
     longer be deemed to be outstanding, and all rights of the holders thereof
     as stockholders of the Corporation (except the right to receive the
     redemption price) will cease. Subject to applicable escheat and similar
     abandoned property laws, any moneys set aside by the Corporation for such
     redemption and unclaimed at the end of six months from the redemption date
     shall revert to the general funds of the Corporation, after which
     reversion the holders of such shares so called for redemption shall look
     only to the general funds of the Corporation for the payment of the
     amounts payable upon such redemption. Any interest accrued on funds so
     deposited shall be paid to the Corporation from time to time.

         Section 4. Mandatory Redemption. Subject to the rights of the holders
     of any class or series of stock ranking prior to the Series A Preferred
     Stock, upon the occurrence of a Mandatory Redemption Event, the
     Corporation shall redeem out of funds legally available therefor all of
     the outstanding shares of Series A Preferred Stock on a date (the
     "Mandatory Redemption Date") not more than 60 days after the date of such
     Mandatory Redemption Event a redemption price of $50.50 per share plus an
     amount equal to accrued and unpaid dividends (whether or not declared)
     thereon to but excluding the Mandatory Redemption Date, including any
     changes in dividends payable due to changes in the annual dividend rate or
     Dividends Received Percentage, and Additional DRD Dividends, if any.

         A "Mandatory Redemption Event" shall mean the earliest to occur of the
     following events:

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<PAGE>   8

              (i) the Transaction (as defined below) shall have been voted upon
         by the stockholders of the Corporation and shall not have been
         approved at the special meeting of Tenneco stockholders presently
         scheduled to be held on December 10, 1996 for the purpose of
         considering and voting upon the Transaction (such meeting having been
         finally adjourned): (ii) the Transaction shall not have been approved
         by the requisite vote of the stockholders of the Corporation entitled
         to vote thereon on or prior to March 31, 1997; or (iii) the
         Corporation shall not have accepted on or prior to March 31, 1997 any
         indebtedness of the Corporation and its subsidiaries tendered to it
         pursuant to the cash tender offers made by it pursuant to the
         Transaction.

         "Transaction" means the reorganization of the Corporation pursuant to
     which (i) the Corporation and its subsidiaries will, pursuant to a
     Distribution Agreement dated as of November 1, 1996 (as such may be
     amended, supplemented or modified from time to time) among the
     Corporation, New Tenneco Inc., a newly formed wholly-owned subsidiary of
     the Corporation ("New Tenneco"), and Newport News Shipbuilding Inc., a
     wholly-owned subsidiary of the Corporation ("Newport News"), undertake
     various intercompany transfers and distributions designed to restructure,
     divide and separate their various businesses and assets so that all of the
     assets, liabilities and operations of (A) their automotive parts,
     packaging and administrative services businesses ("Industrial Business")
     are owned and operated by New Tenneco, and (B) their shipbuilding business
     ("Shipbuilding Business") are owned and operated by Newport News; (ii) the
     Corporation will then distribute pro rata to holders of the common stock
     of the Corporation all of the outstanding common stock of New Tenneco and
     Newport News; and (iii) thereafter a subsidiary of El Paso will merge with
     and into the Corporation, which will then consists of the remaining
     existing and discontinued operations of the Corporation and its
     subsidiaries other than those relating to the Industrial Business or the
     Shipbuilding Business, including the transmission and marketing of natural
     gas, pursuant to the Merger Agreement.

         Notice of redemption pursuant to this Section 4 will be given by mail,
     not less than 30 nor more than 60 days prior to the Mandatory Redemption
     Date to each record holder of shares of Series A Preferred Stock at the
     address of such holder in the stock register of the Corporation. If a
     notice of redemption has been given, from and after the Mandatory
     Redemption Date (unless the Corporation defaults in making payment of the
     redemption price), dividends on the Series A Preferred Stock will cease to
     accrue, such shares will no longer be deemed to be outstanding, and all
     rights of the holders thereof as stockholders of the Corporation (except
     the right to receive the redemption price) will cease. Subject to
     applicable escheat and similar abandoned property laws, and moneys set
     aside by the Corporation for such redemption and unclaimed at the end six
     months from the Mandatory Redemption Date shall revert to the general
     funds of the Corporation, after which reversion the holders of such shares
     so called for redemption shall look only to the general funds of the
     Corporation for the payment of the amounts payable upon such redemption.
     Any interest accrued on funds so deposited shall be paid to the
     Corporation from time to time.

         Section 5. Voting.  The Series A Preferred Stock shall not have any 
     voting rights except as required by law or the Certificate of 
     Incorporation, or as hereinafter set forth:

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<PAGE>   9

              (a) Each share of Series A Preferred Stock shall entitle the
         holder thereof to one vote on all matters submitted to a vote of the
         holders of Series A Preferred Stock.

              (b) The holders of Series A Preferred Stock, voting as separate
         series from all other series of Preferred Stock and classes of capital
         stock, shall be entitled, at each annual meeting of stockholders of
         the Corporation, to elect a number of directors of the Corporation
         equivalent to the smallest number representing at least one-sixth of
         the number of members of the Board of Directors as if there were no
         vacancies or unfilled newly created directorships on such Board,
         without giving effect to any directorships created or directors
         elected pursuant to paragraph (c) below. Any director so elected shall
         hold office until the next annual meeting and until his or her
         successor shall be elected and qualify, subject, however, to prior
         death, resignation, retirement, disqualification or removal from
         office. So long as any shares of Series A Preferred Stock are
         outstanding, the number of members of the Board of Directors of the
         Corporation (as if there were no vacancies or unfilled newly created
         directorships on such Board, without giving effect to any
         directorships created or directors elected pursuant to paragraph (c)
         below) shall be set at an integral multiple of six.

              A director elected pursuant to the terms of this paragraph (b)
         may be removed without cause only by the holders of a majority in
         voting power of the outstanding Series A Preferred Stock.

              At such time as all shares of the Series A Preferred Stock shall
         cease to be outstanding, the term of office of any director elected
         pursuant to this paragraph (b), or his or her successor, shall
         automatically terminate.

              (c) Whenever, at any time or times, dividends payable on the
         Series A Preferred Stock shall be in arrears for dividend periods,
         whether or not consecutive, containing in the aggregate a number days
         equivalent to six calendar quarters, the holders of outstanding Series
         A Preferred Stock shall have the exclusive right, in addition to the
         rights under (b) above, voting as a separate series from all other
         series of Preferred Stock and classes of capital stock of the
         Corporation, at each meeting of the stockholders held for the purpose
         of electing directors, to elect two directors of the Corporation,
         until such time as all dividends accumulated on the Series A Preferred
         Stock and in arrears shall have been paid in full or declared and set
         apart for payment, at which time the right of the holders of the
         Series A Preferred Stock to vote pursuant to the provisions of this
         paragraph (c) shall terminate, subject to revesting in the event of
         each and every subsequent default of the character and for the time
         above mentioned.

              At any time when voting rights shall, pursuant to the provisions
         of this paragraph (c), be vested in the Series A Preferred Stock, the
         number of directors of the Corporation shall be automatically
         increased, to the extent necessary, so that two directors may be
         elected by the holders of the Series A Preferred Stock and a proper
         officer of the Corporation shall, upon the written request of the
         holders of record of at 

                                       9

<PAGE>   10

         least ten percent in aggregate liquidation value of the Series A
         Preferred Stock then outstanding, addressed to the Secretary of the
         Corporation, call a special meeting of holders of the Series A
         Preferred Stock. Such meeting shall be held at the earliest
         practicable date but in no event shall a special meeting be held if
         the annual meeting of the stockholders of the Corporation is to be
         held within 90 days of the receipt by the Secretary of the Corporation
         of such request. If such meeting shall not be called by the proper
         officer of the Corporation as required within 20 days after personal
         service of the said written request upon the Secretary of the
         Corporation, or within 20 days after mailing the same within the
         United States of America by certified or registered mail, return
         receipt requested, addressed to the Secretary of the Corporation at
         its principal office (such mailing to be evidenced by the registry
         receipt issued by the postal authorities), then the holders of record
         of at least ten percent of the aggregate liquidation value of the
         Series A Preferred Stock then outstanding may designate in writing one
         of their number to call such meeting, and such meeting may be called
         by such person designated upon the notice required for annual meetings
         of stockholders but in no event shall a special meeting be held if the
         annual meeting of stockholders of the Corporation is to be held within
         90 days of the receipt by the Secretary of the Corporation of such
         request. Any holder of the Series A Preferred Stock so designated
         shall have access to the stock books of the Corporation for the
         purpose of causing a meeting of stockholders to be called pursuant to
         these provisions.

              Upon any termination of the right of the holders of the Series A
         Preferred Stock to vote for directors as a class as described in this
         paragraph (c), the term of office of the directors so elected as
         described in this paragraph (c) shall automatically terminate and the
         number of directors shall be reduced accordingly.

              (d) At any meeting so called pursuant to paragraph (c) above, and
         at any other meeting of stockholders held for the purpose of electing
         directors at which the holders of the Series A Preferred Stock shall
         have the right to elect directors as provided in paragraph (b) or
         paragraph (c) above, the presence in person or by proxy of a majority
         in voting power of the outstanding shares of the Series A Preferred
         Stock, shall be required to constitute a quorum thereof for the
         election of any director by the holders of the Series A Preferred
         Stock.

              At any such meeting or adjournment thereof, (x) the absence of
         the required quorum of the Series A Preferred Stock shall not prevent
         the election of directors other than those to be elected by the Series
         A Preferred Stock and the absence of a quorum for the election of such
         other directors shall not prevent the election of the directors to be
         elected by the Series A Preferred Stock, and (y) in the absence of
         either or both such quorums, a majority in voting power of the holders
         present in person or by proxy of the stock or stocks which lack a
         quorum shall have power to adjourn the meeting, subject to applicable
         law, for the election of directors which they are entitled to elect
         from time to time without notice other than announcement at the
         meeting until a quorum shall be present.


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<PAGE>   11

              (e) If by reason of any resignation, retirement,
         disqualification, death or removal there are not in office all such
         directors that the holders of the Series A Preferred Stock are
         entitled to elect pursuant to paragraph (c), then any such vacancy
         shall be filled only by the remaining director or directors elected by
         such holders or, only in the event there is no such remaining
         director, by the holders of the Series A Preferred Stock entitled to
         vote thereon. If by reason of any resignation, retirement,
         disqualification, death or removal there are not in office all such
         directors that the holders of the Series A Preferred Stock are
         entitled to elect pursuant to paragraph (b), then any such vacancy
         shall be filled only by a majority of the remaining directors elected
         by such holders or, in the event there are no such remaining
         directors, by the majority vote of the remaining directors then
         constituting the Board of Directors.

              Promptly after the right of the holders of the Series A Preferred
         Stock to fill any vacancy as set forth in the first sentence of the
         immediately preceding paragraph arises, the Board of Directors may
         cause a special meeting of the holders of Series A Preferred Stock
         entitled to vote thereon, to be held for the purpose of filling such
         vacancy and such vacancy shall be filled at any such special meeting.
         Such meeting shall be held at the earliest practicable date, but in no
         event shall a special meeting be held if the annual meeting of
         stockholders of the Corporation is to be held within 90 days of the
         occurrence of such vacancy.

              Notwithstanding the immediately preceding paragraph, at any time
         after the right of the holders of the Series A Preferred Stock to fill
         any vacancy as set forth above in the first sentence of the first
         paragraph of this paragraph (e) arises, a proper officer of the
         Corporation shall, upon the written request of the holders of record
         of at least ten percent in aggregate liquidation value of the Series A
         Preferred Stock then outstanding, addressed to the Secretary of the
         Corporation, call a special meeting of holders of the Series A
         Preferred Stock. Such meeting shall be held at the earliest
         practicable date but in no event shall a special meeting be held if
         the annual meeting stockholders of the Corporation is to be held
         within 90 days of the occurrence of such vacancy. If such meeting
         shall not be called by the proper officer of the Corporation as
         required within 20 days after personal service of the said written
         request upon the Secretary of the Corporation, or within 20 days after
         mailing the same within the United States of America by registered
         mail addressed to the Secretary of the Corporation as its principal
         office (such mailing to be evidenced by the registry receipt issued by
         the postal authorities), then the holders of record of at least ten
         percent of the aggregate liquidation value of the Series A Preferred
         Stock then outstanding may designate in writing one of their number to
         call such meeting, and such meeting may be called by such person
         designated upon the notice required for annual meetings of
         stockholders and shall be held at the place at which the last
         preceding annual meeting of the stockholders of the Corporation was
         held. Any holder of the Series A Preferred Stock so designated shall
         have access to the stock books of the Corporation for the purpose of
         causing a meeting of stockholders to be called pursuant to these
         provisions.

                                      11

<PAGE>   12

              (f) In addition to any other vote or consent of stockholders
         required by law or the Certificate of Incorporation, if any, so long
         as any shares of Series A Preferred Stock are outstanding, the
         Corporation shall not, without the consent of the holders of at least
         a majority in voting power of the outstanding shares of Series A
         Preferred Stock, given in person or by proxy, either in writing or by
         vote at annual meeting or a special meeting called for that purpose:

                  (A) issue any additional shares of Series A Preferred Stock
              (other than the 6,000,000 shares of Series A Preferred Stock
              authorized hereby), or issue any shares of any class or series of
              stock ranking prior to or on parity with the Series A Preferred
              Stock as to the payment of dividends or as to the distribution of
              assets on liquidation, dissolution or winding up:

                  (B) issue any obligations or security convertible into share
              of stock ranking prior to or on parity with the Series A
              Preferred Stock as to the payment of dividends or as the
              distribution of assets on liquidation, dissolution or winding up;
              or

                  (C) amend the Certificate of Incorporation or the Certificate
              of Designation if the amendment would alter or change the powers,
              preferences or special rights of the shares of Series A Preferred
              Stock so as to affect such shares adversely.

         Section 6. Restrictions on Dividends and Stock Repurchases. Subject to
     any additional restrictions or limitations contained in the Certificate of
     Incorporation, if any, so long as any shares of Series A Preferred Stock
     remain outstanding, unless full cumulative dividends on the outstanding
     shares of Series A Preferred Stock for all past dividend periods have been
     paid, or declared and set apart for payment, and the Corporation shall not
     be in default with respect to its obligations under Section 4 hereof,
     dividends may not be paid or declared and other distributions may not be
     made upon any class or series of stock of the Corporation ranking junior
     to or on a parity with the Series A Preferred Stock as to dividends or
     rights upon dissolution, liquidation or winding up of the Corporation nor
     may any such class or series of stock of the Corporation be purchased,
     retired or otherwise acquired by the Corporation, in either case without
     the consent, given in person or by proxy, either in writing or by vote at
     any annual meeting or as a special meeting called for that purpose, of the
     holders of at least a majority in voting power of the outstanding shares
     of Series A Preferred Stock present in person or by proxy at such meeting,
     provided that quorum, consisting of at least a majority in voting power of
     the then outstanding shares of Series A Preferred Stock is present;
     provided, however, that, notwithstanding the foregoing provisions of this
     Section 6 (but subject to any restrictions or limitations to the contrary
     contained in the Certificate of Incorporation), the Corporation may any
     time redeem, purchase or acquire, out of funds legally available therefor,
     shares of stock ranking junior to or on a parity with the Series A
     Preferred Stock as to dividends and rights upon liquidation, dissolution
     and winding up of the Corporation in exchange for, or out of net cash
     proceeds from a substantially concurrent sale of, other shares of any
     stock of the 

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<PAGE>   13

     Corporation ranking junior to the Series A Preferred Stock as to
     dividends and rights upon liquidation, dissolution and winding up.

         Section 7.  Ranking. (a) Any class or series of stock of the 
     Corporation shall be deemed to rank:

              (i) prior to the Series A Preferred Stock as to the payment of
         dividends or as to distributions of assets upon liquidation,
         dissolution or winding up, as the case may be, if the holders of such
         class or series shall be entitled to the receipt of dividends or of
         amounts distributable upon liquidation, dissolution or winding up, as
         the case may be, in preference or priority to the holders of Series A
         Preferred Stock:

              (ii) on a parity with the Series A Preferred Stock as to the
         payment of dividends, whether or not the dividend rates or dividend
         payment dates thereof be different from those of the Series A
         Preferred Stock, if the holders of such class or series of stock and
         the holders of the Series A Preferred Stock shall be entitled to the
         receipt of dividends in proportion to their respective amounts of
         accrued and unpaid dividends per share, without preference or priority
         one over the other, and on a parity with the Series A Preferred Stock
         as to the distribution of assets upon liquidation, dissolution or
         winding up, whether or not the liquidation prices per share thereof be
         different from those of the Series A Preferred Stock, if the holders
         of such class or series of stock and the holders of the Series A
         Preferred Stock shall be entitled to the receipt of amounts
         distributable upon liquidation, dissolution or winding up in
         proportion to their respective liquidation preferences, without
         preference or priority one over the other: and

              (iii) junior to the Series A Preferred Stock as to the payment of
         dividends or as to the distribution of assets upon liquidation,
         dissolution or winding up, as the case may be, if the holders of
         Series A Preferred Stock shall be entitled to receipt of dividends or
         of amounts distributable upon liquidation, dissolution or winding up,
         as the case may be, in preference or priority to the holders of shares
         of such class or series.

         (b) Except for the Common Stock, par value $5.00 per share, of the
     Corporation (as such may be constituted from time to time, the "Common
     Stock") and the Series A Participating Junior Preferred Stock, without par
     value, of the Corporation (the "Participating Junior Preferred Stock"),
     each other class and series of stock of the Corporation existing on the
     date of the adoption of this Certificate shall be deemed to rank prior to
     the Series A Preferred Stock both as to the payment of dividends and as to
     the distribution of assets upon liquidation, dissolution or winding up.
     The Common Stock and the Participating Junior Preferred Stock shall be
     deemed to rank junior to the Series A Preferred Stock both as to the
     payment of dividends and as to the distribution of assets upon
     liquidation, dissolution or winding up.

         Section 8. Liquidation Rights. (a) The amount that the holders of
     Series A Preferred Stock shall be entitled to receive in the event of any
     dissolution, liquidation or winding up of the affairs of the Corporation,
     whether voluntary or involuntary (collectively, a 

                                      13

<PAGE>   14

     "Liquidation"), shall be $50.00 per share, plus an amount equal to all
     accrued and unpaid dividends to the date of Liquidation including any
     changes in dividends payable due to changes in the annual dividend
     rate of Dividends Received Percentage, and Additional DRD Dividends,
     if any, and no more. After such amount is paid in full, no further
     distributions or payments shall be made in respect of shares of Series
     A Preferred Stock, such shares of Series A Preferred Stock shall no
     longer be deemed to be outstanding or be entitled to any powers,
     preferences, rights or privileges, including voting rights, and such
     shares of Series A Preferred Stock shall be surrendered for
     cancellation to the Corporation.

         (b) In the event of any liquidation, dissolution or winding up of the
     affairs of the Corporation, then before any distribution or payment shall
     be made to the holders of any class or series of stock of the Corporation
     ranking junior to the Series A Preferred Stock, the holders of the Series
     A Preferred Stock (subject to the rights of the holders of any stock
     ranking prior to the Series A Preferred Stock as to the rights on
     liquidation, dissolution and winding up) shall be entitled to be paid in
     full the amounts set forth in paragraph (a) of this Section 8. After such
     payment shall have been made in full to the holders of the Series A
     Preferred Stock, the remaining assets and funds of the Corporation shall
     be distributed among the holders of the stock of the Corporation ranking
     junior in respect thereof to the Series A Preferred Stock according to
     their respective rights. In the event that the assets of the Corporation
     available for distribution to holders of Series A Preferred Stock shall
     not be sufficient to make the payment herein required to be made in full
     and to pay in full the liquidation preference on all other shares of stock
     of the Corporation ranking on a parity with the Series A Preferred Stock
     as to amounts distributable upon dissolution, liquidation or winding up of
     the Corporation, such assets shall be distributed to the holders of the
     respective shares of Series A Preferred Stock and any such other parity
     stock pro rata in proportion to the full amounts payable upon the shares
     of Series A Preferred Stock and any such other parity stock if all amounts
     payable thereon were paid in full.

         Section 9. Maturity.  Unless otherwise redeemed as provided herein,  
     the term of the Series A Preferred Stock shall be perpetual.

         FIFTH: (A) The number of directors which shall constitute the whole
Board of Directors shall be as determined from time to time by resolution
adopted by the affirmative vote of a majority of the Board of Directors;
provided that until otherwise determined by the Board of Directors in
accordance herewith, the number of directors shall be six (6).

         (B) In furtherance and not in limitation of the powers which are now
or may hereafter be conferred by statute or the By-Laws of the Corporation, the
Board of Directors is expressly authorized:

         (a) To fix, determine and vary from time to time the amount to be
maintained as surplus and the amount or amounts to be set apart as working
capital.


                                      14
<PAGE>   15

         (b) To set apart out of any of the funds of the Corporation available
for dividends a reserve or reserves for any proper purposes and/or to abolish
any such reserve in the manner in which it was created.

         (c) To make, amend, alter, change, add to or repeal By-Laws for the
Corporation, without any action on the part of the stockholders. The By-Laws
made by the Board of Directors may be amended, altered, changed, added to or
repealed by the stockholders.

         (d) To authorize and cause to be executed mortgages and liens, without
limit as to amount, upon the real and personal property of the Corporation.

         (e) From time to time to determine whether and to what extent, at what
time and place, and under what conditions and regulations the accounts and
books of the Corporation or any of them, shall be open to the inspection of any
stockholder, and no stockholder shall have any right to inspect any account or
book or document of the Corporation except as conferred by statute or the
By-Laws or as authorized by a resolution of the stockholders or the Board of
Directors.

         (f) To authorize the payment of compensation to the directors for
services to the Corporation, including fees for attendance at meetings of the
Board of Directors, and of any committees, and to determine the amount of such
compensation and fees.

         (g) To designate by resolution or resolutions, passed by a majority of
the whole Board of Directors, one or more committees, which, to the extent
provided in said resolution or resolutions or in the By-laws of the
Corporation, shall have and may exercise the powers of the Board of Directors
in the management of the business and affairs of the Corporation and may have
power to authorize the seal of the Corporation to be affixed to all papers
which may require it.

         (h) At any time or from time to time (without any action by the
stockholders of the Corporation) to create and issue, whether or not in
connection with the issue and sale of any shares of stock of other securities
of the Corporation, rights or options entitling the holders thereof to purchase
from the Corporation any shares of its capital stock of any class or classes or
of any series of any class or classes, such rights or options to be evidenced
by or in such instrument or instruments as shall be approved by the Board of
Directors. The terms upon which, the time or times, which may be limited or
unlimited in duration, at or within which, and the price or prices at which any
such shares may be purchased from the Corporation upon the exercise of any such
right or option shall be such as shall be fixed and stated in the resolution or
resolutions adopted by the Board of Directors providing for the creation and
issue of such rights or options and, in every case, set forth or incorporated
by reference in the instrument or instruments evidencing such rights or
options.

         SIXTH:  Omitted.

         SEVENTH:  The Corporation is to have perpetual existence.

                                      15

<PAGE>   16

         EIGHTH: A director of this corporation shall not be liable to the
Corporation or its stockholders for monetary damages for breach of fiduciary
duty as a director, except for liability (i) for any breach of the director's
duty of loyalty to the Corporation or its stockholders, (ii) for acts or
omissions not in good faith or which involve intentional misconduct or a
knowing violation of the law, (iii) under Section 174 of the General
Corporation Law of the State of Delaware, or (iv) for any transaction from
which the director derived an improper personal benefit.

         IN WITNESS WHEREOF, El Paso Tennessee Pipeline Co., has caused this
Restated Certificate of Incorporation to be signed by a duly authorized officer
this 11th day of May 1999.

                                             EL PASO TENNESSEE PIPELINE CO.



                                             By:   /s/ Jeffrey I. Beason
                                                 ------------------------------
                                                       Jeffrey I. Beason
                                                 Vice President and Controller








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