Chance, destiny, and the inner workings of ClpXP

Abstract

AAA+ proteases are responsible for protein degradation in all branches of life. Using single-molecule and ensemble assays, Cordova et al. investigate how the bacterial protease ClpXP steps through a substrate's polypeptide chain and construct a quantitative kinetic model that recapitulates the interplay between stochastic and deterministic behaviors of ClpXP.

Figure 1. Substrate Degradation by the ClpXP protease

The ClpX ATPase ring is shown with ATP-bound subunits in red and free subunits in grey. The dice faces symbolize the finding that any subunit loaded with ATP can initiate a chain of ATP hydrolysis reactions. The proteolytic ClpP rings are depicted in grey; their proteolytic sites are buried at the center and therefore not visible.