Underlying Mechanisms of Mitochondria-related 

Diseases through Cardiolipin-Cytochrome C 

Interactions 

Compiled by: Surabhi Singh 

Mentor: Dr. Minh Phan

Comentor: Dr. Sushil Satija

Host Lab: NIST Center for Neutron Research

1
Key Components

Highly negative and unsaturated

Alterations to its structure and 

concentration lead to disease

Cytoc hrome 

c

Cardiolipin

anchored to the outside of 

phospholipid membrane by 

CL

Figure 2: Ofoedu, Chigozie, Foods 2021, 10, 699

Figure 1:

2
Internal Biosynthetic Pathway and Diseases

He art Failure → decreased CL levels 

Isc he mia and re pe rfusion → decreased CL levels 

Linoleic acid species diminish

Diabetic cardiomyopathy → decreased CL levels

Barth Syndrome → increase in MLCL 

(monolysocardiolipin)

Figure 3:

3
Motivation behind Project

Adsorbed 

Integrated

DP 

System

DM 

System

4
Techniques Employed

Langmuir isothe rm:

Fabricate the film that have the same packing 

density as the inner mitochondria 

(25mN/m)

Mix with different lipids to mimic the real 

membrane

X-Ray Refle c tome try

Allows us to get information about the 

thickness, density, roughness of 

membrane film

Adsorption Assay

Measure how much protein is absorbed by 

the interface and how it interacts with the 

membrane (how fast or slow)

5
I. Conc e ntration Effe ct

Isotherm Data: DMPC:DMPE w/ varied concentrations of healthy CL (18:2)4CL

DMPC:DMPE:4CL @ 0.15, 0.20, 0.40 (mole percent)

0.40 has 

faster takeoff 

point Unable to define 

plateau

6
I. Effe cts of Structural Cha nge s 

- Disea se d CL 

Isotherm Data: DMPC:DMPEMLCL

7
I. Conc e ntration Effe cts - He althy Me mbrane Mode l

XRR Data DMPC:DMPE:4CL @0.20

Additional 

fringe → 

Homogeneous 

protein binding

Nonhomogenou

s

proteins

Homogenous, 

dense

8
I. Conc e ntration Effe cts - Disea se d Me mbrane Mode l

XRR Data DMPC:DMPE:4CL @0.15

Homogeneous protein binding, but less than 0.20 

proteins

Homogenous, less dense

9
I. Effe cts of Structural Cha nge s - Disea se d CL 

XRR Data DMPC:DMPE:MLCL

MLCL associates less tightly with proteins 

than CL does → Less homogenous binding 

Homogenous, lesser dense

10
Conclusion

At pressures before 25 mN/m, 

- As CL concentration increases in the fabricated membrane, the phase transition is less 

prominent

- The MLCL- and healthy CL-containing membranes have almost identical phase behaviors

In membranes w/ lower concentration of CL mass (0.15), the binding of CytC is less homogenous 

than the binding of the membrane w/ 0.20 CL

- When MLCL is introduced, CytC is much less absorbed in the membrane.

How CytC binding affects the membrane structure still requires further analysis of X-ray (is the 

membrane in tact or disrupted?)

The de c re ase in CytC binding lea ds to the progression of meta bolic dise ase s

11
Acknowledgements

Dr. Minh Phan - Mentor

Dr. Sushil Satija - Co-mentor

Sanjana Sureshbabu - Lab Partner

NCNR SURF Directors - Julie Borchers - Susana Teixeira - Leland Harriger

NIST SURF - Cara O’Malley

12
Backup Slides
I. Conc e ntration Effe ct

Isotherm Data: DP- System w/ varied concentrations of healthy CL (18:2)4CL

Figure 4:

DPPC:DPPE:4CL @ 0.15, 0.20, 0.40 (mole percent)

- CL is rigid → very dynamic and able to 

communicate w/ other molecules easily

- CL favors disorder →diminishes the 

plateau

Blue → earlier 

takeoff point

Blue → 

plateau not 

observed

Grey and 

red plateau 

visible

-

0.69

–0.71

-0.87

-2.6

-2.3

-2.0
Adsorption Assay: DPPC:DPPE:4CL (0.40 concentration) 
XRR Data DPPC:DPPE:4CL @0.20

No horizontal 

shift in Kiessig 

fringe

Q ~ 2π/d Left or right shift of Kiessig 

fringe shows us change in 

thickness of membrane

The less pronounced the Kiessig fringe is at 

equilibrium, the more rough our membrane is 

→ Cytc bounded less homogenous

proteins

Homogenous

Less homogenous
XRR Data DPPC:DPPE:4CL @0.40

Additional oscillation/fringe present → Cytc 

formed homogenous layer under membrane, 

Red shifted left →thickness of membrane 

increased 

- More thick, better binding of protein

proteins

Homogenous
XRR Data DMPC:DMPE:DMPG

Homogenous protein binding in 

in initial injection stage and 

equilibrium 
Isotherm Data: DM System w/ control (DMPG)

DMPC:DMPE:DMPG