Related Experiment Video
Updated: May 24, 2026

Atomic Scale Structural Studies of Macromolecular Assemblies by Solid-state Nuclear Magnetic Resonance Spectroscopy
Published on: September 17, 2017
Reconstruction of protein side-chain conformational free energy surfaces from NMR-derived methyl axis order
Marimuthu Krishnan1, Jeremy C Smith
1Center for Computational Natural Sciences and Bioinformatics, International Institute of Information Technology, Hyderabad 500 032, India. m.krishnan@iiit.ac.in
Abstract:
An analytical approach is developed for reconstructing site-specific methyl-bearing protein side-chain conformational energy surfaces from NMR methyl axis order parameters (O(axis)(2)). Application of an enhanced sampling algorithm (adaptive biasing force) to molecular dynamics simulation of a protein, calcium-bound calmodulin, reveals a nonlinear correlation between O(axis)(2) and the populations of rotamer states of protein side-chains, permitting the rotamer populations to be extracted directly from O(axis)(2). The analytical approach yields side-chain conformational distributions that are in excellent agreement with those obtained from the enhanced-sampling MD results.
Related Concept Videos
¹H NMR of Conformationally Flexible Molecules: Temporal Resolution
Newman Projections
The organic molecules rotate across the single bonds leading to numerous temporary three-dimensional structures of varying energy known as conformers.
¹H NMR of Conformationally Flexible Molecules: Variable-Temperature NMR
Fischer Projections

