Biotechnology and Biological Sciences Research Council (BBSRC) [a doctoral training grant Ph.D. studentship to S.W. and project grant number BB/I008675/1] and the Wellcome Trust [project grant number 084452]

Alice Robson

Bauer

Blobel

Breyton

Brundage

Cannon

Deville

Ding

Erlandson

Gelis

Gold

Gouridis

Hizlan

Hunt

Ian Collinson

Kimura

Osborne

Park

Plath

Robson

Sarah Whitehouse

van den Berg

Vicki A. M. Gold

Whitehouse

Woodbury

Zimmer

Biochemical Journal

English

PubMed

The motor ATPase SecA drives protein secretion through the bacterial Sec complex. The PPXD (pre-protein cross-linking domain) of the enzyme has been observed in different positions, effectively opening and closing a clamp for the polypeptide substrate. We set out to explore the implicated dynamic role of the PPXD in protein translocation by examining the effects of its immobilization, either in the position occupied in SecA alone with the clamp held open or when in complex with SecYEG with the clamp closed. We show that the conformational change from the former to the latter is necessary for high-affinity association with SecYEG and a corresponding activation of ATPase activity, presumably due to the PPXD contacting the NBDs (nucleotide-binding domains). In either state, the immobilization prevents pre-protein transport. However, when the PPXD was attached to an alternative position in the associated SecYEG complex, with the clamp closed, the transport capability was preserved. Therefore large-scale conformational changes of this domain are required for the initiation process, but not for translocation itself. The results allow us to refine a model for protein translocation, in which the mobility of the PPXD facilitates the transfer of pre-protein from SecA to SecYEG.</jats:p

Crossref

The dynamic action of SecA during the initiation of protein translocation

Gold, VAM

Whitehouse, S

Robson, A

Collinson, I

Queen Mary Research Online

A large conformational change couples the ATP binding site of SecA to the SecY protein channel.

Energy transduction in protein transport and the ATP hydrolytic cycle of SecA.

The action of cardiolipin on the bacterial translocon.

The oligomeric state and arrangement of the active bacterial translocon.

The SecA ATPase Reaction Cycle and its Consequence in Protein Translocation.

Gold, Vicki A M

Robson, Alice

Whitehouse, Sarah

Collinson, Ian R

Explore Bristol Research

http://www.biochemj.org/content/ppbiochemj/449/3/695.full.pdf

The dynamic action of SecA during the initiation of protein translocation

Abstract

Similar works

Full text

Available Versions

Crossref

Queen Mary Research Online

Explore Bristol Research