Finite temperature string method with umbrella sampling using path collective variables: application to secondary
Avijeet Kulshrestha1, Sudeep N Punnathanam1, K Ganapathy Ayappa1
1Department of Chemical Engineering, Indian Institute of Science, Bangalore, 560012, India. sudeep@iisc.ac.in.
Soft Matter
|September 27, 2022
Summary
Studying complex protein structural changes like alpha-helix to beta-sheet transitions is challenging. This research uses path collective variables and the finite temperature string method to reveal the molecular mechanisms of protein conformational changes.
Area of Science:
- Biophysics
- Computational Biology
- Protein Dynamics
Background:
- Protein conformational changes, particularly the transition from alpha-helix to beta-sheet structures, are fundamental to biomolecular systems but difficult to simulate due to long timescales.
- Direct molecular dynamics simulations are often computationally prohibitive for studying these slow transitions.
- Indirect methods, such as free energy landscape calculations, are employed but require appropriate collective variables to describe the process.
Purpose of the Study:
- To determine the molecular mechanisms underlying the structural transition of a mini G-protein from an alpha-helix to a beta-hairpin.
- To demonstrate the utility of path collective variables combined with the finite temperature string method for studying complex protein conformational changes.
- To provide a computational framework for analyzing secondary structure transitions.
Main Methods:
- Utilized path collective variables and the finite temperature string (FTS) method to model protein conformational changes.
- Employed umbrella sampling simulations to generate configurations along the computed transition path.
- Applied weighted histogram analysis to calculate the free energy landscape of the transition.
Main Results:
- The study elucidated the transition pathway from an alpha-helix to a beta-hairpin, involving unfolding of terminal residues and formation of a beta-turn intermediate.
- Successfully demonstrated the effectiveness of the combined path collective variable and FTS approach for complex protein dynamics.
- The free energy landscape along the transition path was successfully computed.
Conclusions:
- The combination of path collective variables and the finite temperature string method is a powerful approach for investigating complex protein conformational changes, including alterations in secondary structure.
- This methodology overcomes the limitations of direct simulations for studying slow biomolecular processes.
- The findings provide insights into the mechanisms of protein folding and structural rearrangements.
