Calculation of minimum energy pathways in transport proteins

Area of Science:

• Biochemistry
• Structural Biology
• Computational Biology

Background:

• Static protein structures are known, but dynamic transitions are hard to study.
• Understanding protein conformational changes is key to biological function.

Purpose of the Study:

• To present a computationally inexpensive algorithm, "cold-inbetweening," for generating protein transition pathways.
• To apply this algorithm to gain mechanistic insights into membrane transporter function.

Main Methods:

• Developed and applied the "cold-inbetweening" algorithm.
• Generated transition trajectories between experimentally determined protein end-states.
• Studied three membrane transporters: DraNramp, MalT, and MATE.

Main Results:

• Simulated elevator transport in MalT via helix unwinding.
• Observed sequential gate closure in DraNramp, supporting the alternate access model.
• Revealed conformational switching in MATE involving helix rewinding to prevent clashes and occlude the ligand-binding site.

Conclusions:

• "Cold-inbetweening" provides mechanistic insights into protein conformational changes.
• The algorithm can generate testable hypotheses about functionally relevant protein dynamics.
• This approach aids in understanding the alternate access mechanism in membrane transporters.