Use of Coarse-Grained and All-Atom Molecular Dynamics to Study Hsp70 and Hsp40 Chaperone Action

The 70 kDalton (Hsp70) chaperones perform a variety of functions in living cells, the most crucial being assisting correct protein folding, refolding misfolded proteins, and participating in iron-sulfur cluster biogenesis. The chaperones consist of the nucleotide-binding domain which, upon transitions between the ADP- to ATPbound state, undergoes slight conformational changes, which trigger major conformational changes in the conformation of the whole molecule, ultimately leading to substrate binding or release. This chapter summarizes our work on the simulations of the chaperone cycle by means of all-atom and coarse-grained molecular dynamics, and on modeling the structure and interactions of two complexes that are formed during the process of iron-sulfur biogenesis: the binary complex composed of the Iron-sulfur protein 1 and the Jac1 Hsp40 cochaperone from yeast, and the ternary complex composed of the Iron-sulfur protein 1, the Jac1 Hsp40 cochaperone, and the Stressseventy subfamily Q protein 1 Hsp70 chaperone from yeast.

Keywords: Hsp70 chaperones, Chaperone cycle, Iron-sulfur biogenesis, Molecular modeling, Molecular dynamics.