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

J. Biol. Chem., Vol. 283, Issue 18, 12276-12283, May 2, 2008

This Article Full Text Full Text (PDF) All Versions of this Article: 283/18/12276    most recent M710338200v1 Alert me when this article is cited 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 Google Scholar Articles by Elbaz, Y. Articles by Schuldiner, S. PubMed PubMed Citation Articles by Elbaz, Y. Articles by Schuldiner, S. Social Bookmarking                      What's this?

Identification of a Glycine Motif Required for Packing in EmrE, a Multidrug Transporter from Escherichia coli^*

From the Department of Biological Chemistry, Alexander A. Silberman Institute of Life Sciences, Hebrew University of Jerusalem, 91904 Jerusalem, Israel

Glycine residues may play functional and structural roles in membrane proteins. In this work we studied the role of glycine residues in EmrE, a small multidrug transporter from Escherichia coli. EmrE extrudes various drugs across the plasma membrane in exchange with protons and, as a result, confers resistance against their toxic effects. Each of 12 glycine residues was replaced by site-directed mutagenesis. Four of the 12 glycine residues in EmrE are evolutionary conserved within the small multidrug resistance family of multidrug transporters. Our analysis reveals that only two (Gly-67 and Gly-97) of these four highly conserved residues are essential for transporter activity. Moreover, two glycine positions that are less conserved, Gly-17 and Gly-90, demonstrate also a nil phenotype when substituted. Our present results identifying Gly-17 and Gly-67 as irreplaceable reinforce the importance of previously defined functional clusters. Two essential glycine residues, Gly-90 and Gly-97, form a protein motif in which glycine residues are separated by six other residues (GG7). Upon substitution of glycine in these positions, the protein ability to form dimers is impaired as evaluated by cross-linking and pull-down experiments.

Received for publication, December 9, 2007 , and in revised form, February 25, 2008.

^* This work was supported in part by National Institute of Health Grant NS16708 and Israel Science Foundation Grant 119/04. 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.

¹ Both authors contributed equally.

² Supported by the Adams Fellowship Program of the Israel Academy of Sciences and Humanities.

³ To whom correspondence should be addressed. Tel.: 972-2-6585992; Fax: 972-2-5634625; E-mail: Shimon.Schuldiner{at}huji.ac.il.

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