Accounting for a mirror-image conformation as a subtle effect in protein folding

作者：Kachlishvili Khatuna; Maisuradze Gia G; Martin Osvaldo A; Liwo Adam; Vila Jorge A; Scheraga Harold A^*

来源：Proceedings of the National Academy of Sciences, 2014, 111(23): 8458-8463.

DOI：10.1073/pnas.1407837111

• misfolding
• symmetrical proteins

By using local (free-energy profiles along the amino acid sequence and C-13(alpha) chemical shifts) and global (principal component) analyses to examine the molecular dynamics of protein-folding trajectories, generated with the coarse-grained united-residue force field, for the B domain of staphylococcal protein A, we are able to (i) provide the main reason for formation of the mirror-image conformation of this protein, namely, a slow formation of the second loop and part of the third helix (Asp29-Asn35), caused by the presence of multiple local conformational states in this portion of the protein; (ii) show that formation of the mirror-image topology is a subtle effect resulting from local interactions; (iii) provide a mechanism for how protein A overcomes the barrier between the metastable mirror-image state and the native state; and (iv) offer a plausible reason to explain why protein A does not remain in the metastable mirror-image state even though the mirror-image and native conformations are at least energetically compatible.

• 出版日期2014-6-10