Conformational Ensemble of B Chain in $T_{6}$ Human Insulin Based on the Landau Free Energy

Insulin is an important peptide hormone for the glucose metabolism. The structural flexibility of insulin B chain attracts a lot of our attention for understanding the biological activity. Our work carried out the extensive sampling to statistically clarify the structural changes of isolated $T_{6}$ human insulin B chain. We introduced the Landau free energy to describe the isolated insulin B chain whose experimental structure locates a local energy minimum. Its trained model was subjected to thousands of heating and cooling circles between the high and low temperatures. Six typical structure clusters were found by classifying the final generated structures with RMSD and radius of gyration. The structures in clusters indicate the potential deformations of insulin B chain at residues 5-8 of N-terminus, residues 9-12 of central helix and residues 24-29 of C-terminus, which agrees with the experimental results.