HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

J. Biol. Chem., Vol. 282, Issue 7, 4661-4668, February 16, 2007

This Article Full Text Full Text (PDF) All Versions of this Article: 282/7/4661    most recent M610828200v1 Submit a Letter to Editor Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Jilaveanu, L. B. Articles by Oliver, D. B. Search for Related Content PubMed PubMed Citation Articles by Jilaveanu, L. B. Articles by Oliver, D. B. Social Bookmarking                      What's this?

In Vivo Membrane Topology of Escherichia coli SecA ATPase Reveals Extensive Periplasmic Exposure of Multiple Functionally Important Domains Clustering on One Face of SecA^*

From the Department of Molecular Biology and Biochemistry, Wesleyan University, Middletown, Connecticut 06459

The Sec-dependent protein translocation pathway promotes the transport of proteins into or across the bacterial plasma membrane. SecA ATPase has been shown to be a nanomotor that associates with its protein cargo as well as the SecYEG channel complex and to undergo ATP-driven cycles of membrane insertion and retraction that promote stepwise protein translocation. Previous studies have shown that both the 65-kDa N-domain and 30-kDa C-domain of SecA appear to undergo such membrane cycling. In the present study we performed in vivo sulfhydryl labeling of an extensive collection of monocysteine secA mutants under topologically specific conditions to identify regions of SecA that are accessible to the trans side of the membrane in its membrane-integrated state. Our results show that distinct regions of five of six SecA domains were labeled under these conditions, and such labeling clusters to a single face of the SecA structure. Our results demarcate an extensive face of SecA that interacts with SecYEG and is in fluid contact with the protein-conducting channel. The observed domain-specific labeling patterns should also provide important constraints on model building efforts in this dynamic system.

Received for publication, November 22, 2006

^* This work was supported by Grant GM42033 from NIGMS, National Institutes of Health. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

The on-line version of this article (available at http://www.jbc.org) contains supplemental Figs. S1–S3.

¹ To whom correspondence should be addressed: Molecular Biology and Biochemistry Dept., Wesleyan University, Middletown, CT 06457. Tel.: 860-685-3556; Fax: 860-685-2141; E-mail: doliver{at}wesleyan.edu.

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				B. A. Bensing and P. M. Sullam Characterization of Streptococcus gordonii SecA2 as a Paralogue of SecA J. Bacteriol., June 1, 2009; 191(11): 3482 - 3491. [Abstract] [Full Text] [PDF]