Clipping along.

摘要

In this issue of/MB, Rajendar and Lucius report a study of the mechanism of polypeptide translocation catalyzed by the Escherichia coli ClpA enzyme-the motor component of the ATP-dependent protease, ClpAP. ATP-dependent proteases play important roles in protein turnover and share a common architecture across organisms. ClpAP is composed of the hexameric AAA+ motor protein ClpA and the tetradecameric serine protease ClpP. The motor component, ClpA, couples the energy from ATP binding and hydrolysis to enzyme-catalyzed protein unfolding and polypeptide translocation. ClpA moves proteins targeted for degradation into the central cavity of the proteolytic component, ClpP, a barrel-shaped protease. ClpA, in the absence of ClpP, also functions to form active RepA monomers from inactive dimers.