Sites of interaction of a precursor polypeptide on the export chaperone SecB mapped by site-directed spin labeling.

ABSTRACT: Export of protein into the periplasm of Escherichia coli via the general secretory system requires that the transported polypeptides be devoid of stably folded tertiary structure. Capture of the precursor polypeptides before they fold is achieved by the promiscuous binding to the chaperone SecB. SecB delivers its ligand to export sites through its specific binding to SecA, a peripheral component of the membrane translocon. At the translocon the ligand is passed from SecB to SecA and subsequently through the SecYEG channel. We have previously used site-directed spin labeling and electron paramagnetic resonance spectroscopy to establish a docking model between SecB and SecA. Here we report use of the same strategy to map the pathway of a physiologic ligand, the unfolded form of precursor gal

SUBMITTER: Crane JM 

PROVIDER: S-EPMC2925277 | biostudies-literature | 2006 Oct

REPOSITORIES: biostudies-literature