Translocation pathway of protein substrates in ClpAP protease.

ABSTRACT: Intracellular protein degradation, which must be tightly controlled to protect normal proteins, is carried out by ATP-dependent proteases. These multicomponent enzymes have chaperone-like ATPases that recognize and unfold protein substrates and deliver them to the proteinase components for digestion. In ClpAP, hexameric rings of the ClpA ATPase stack axially on either face of the ClpP proteinase, which consists of two apposed heptameric rings. We have used cryoelectron microscopy to characterize interactions of ClpAP with the model substrate, bacteriophage P1 protein, RepA. In complexes stabilized by ATPgammaS, which bind but do not process substrate, RepA dimers are seen at near-axial sites on the distal surface of ClpA. On ATP addition, RepA is translocated through approximately 150 A in

SUBMITTER: Ishikawa T 

PROVIDER: S-EPMC31834 | biostudies-literature | 2001 Apr

REPOSITORIES: biostudies-literature