Processive chitinase is Brownian monorail operated by fast catalysis after peeling rail from crystalline chitin.

ABSTRACT: Processive chitinase is a linear molecular motor which moves on the surface of crystalline chitin driven by processive hydrolysis of single chitin chain. Here, we analyse the mechanism underlying unidirectional movement of Serratia marcescens chitinase A (SmChiA) using high-precision single-molecule imaging, X-ray crystallography, and all-atom molecular dynamics simulation. SmChiA shows fast unidirectional movement of ~50 nm s^-1 with 1 nm forward and backward steps, consistent with the length of reaction product chitobiose. Analysis of the kinetic isotope effect reveals fast substrate-assisted catalysis with time constant of ~3 ms. Decrystallization of the single chitin chain from crystal surface is the rate-limiting step of movement with time constant of ~17 ms, achieved by bin

SUBMITTER: Nakamura A 

PROVIDER: S-EPMC6145945 | biostudies-literature | 2018 Sep

REPOSITORIES: biostudies-literature