Balancing Disorder and Structure in Force Fields

Background: Molecular dynamics force fields utilize fixed partial charges to approximate interatomic interactions, yet these parameters often struggle to accurately represent the conformational landscape of flexible peptides that transition between disordered and ordered states.

Question / Future Work: There remains a significant challenge in balancing the propensity for intrinsic disorder against the formation of stable secondary structures within fixed-charge force field frameworks. Specifically, it is currently unclear how to parameterize force fields to correctly capture conformational selection mechanisms across diverse peptide sequences without introducing systematic structural biases. This bottleneck necessitates the development of new strategies to refine fixed-charge models or move toward polarizable models that can better represent the energetic competition between solvent-solute and solute-solute interactions in flexible systems.

Why It Matters: This is a fundamental limitation in molecular simulations of intrinsically disordered proteins and peptides, impacting drug discovery and structural biology predictions where the native state is highly dynamic.

Evidence: The study highlights limitations in current force fields’ ability to balance disorder and secondary structure, particularly when modeling conformational selection.