Stochastic but highly coordinated protein unfolding and translocation by the ClpXP proteolytic machine.

ABSTRACT: ClpXP and other AAA+ proteases recognize, mechanically unfold, and translocate target proteins into a chamber for proteolysis. It is not known whether these remarkable molecular machines operate by a stochastic or sequential mechanism or how power strokes relate to the ATP-hydrolysis cycle. Single-molecule optical trapping allows ClpXP unfolding to be directly visualized and reveals translocation steps of ∼1-4 nm in length, but how these activities relate to solution degradation and the physical properties of substrate proteins remains unclear. By studying single-molecule degradation using different multidomain substrates and ClpXP variants, we answer many of these questions and provide evidence for stochastic unfolding and translocation. We also present a mechanochemical model that accoun

SUBMITTER: Cordova JC 

PROVIDER: S-EPMC4134808 | biostudies-literature | 2014 Jul

REPOSITORIES: biostudies-literature