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

J. Biol. Chem., Vol. 281, Issue 13, 8898-8906, March 31, 2006

This Article Full Text Full Text (PDF) All Versions of this Article: 281/13/8898    most recent M512415200v1 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 Schlenker, O. Articles by Wild, K. Search for Related Content PubMed PubMed Citation Articles by Schlenker, O. Articles by Wild, K. Social Bookmarking                      What's this?

The Structure of the Mammalian Signal Recognition Particle (SRP) Receptor as Prototype for the Interaction of Small GTPases with Longin Domains^*

From the Biochemie-Zentrum der Universität Heidelberg (BZH), Im Neuenheimer Feld 328, D-69120 Heidelberg, Germany

The eukaryotic signal recognition particle (SRP) and its receptor (SR) play a central role in co-translational targeting of secretory and membrane proteins to the endoplasmic reticulum. The SR is a heterodimeric complex assembled by the two GTPases SR and SR, which is membrane-anchored. Here we present the 2.45-Å structure of mammalian SR in its Mg²⁺ GTP-bound state in complex with the minimal binding domain of SR termed SRX. SR is a member of the Ras-GTPase superfamily closely related to Arf and Sar1, while SRX belongs to the SNARE-like superfamily with a fold also known as longin domain. SRX binds to the P loop and the switch regions of SR-GTP. The binding mode and structural similarity with other GTPase-effector complexes suggests a co-GAP (GTPase-activating protein) function for SRX. Comparison with the homologous yeast structure and other longin domains reveals a conserved adjustable hydrophobic surface within SRX which is of central importance for the SR-GTP:SRX interface. A helix swap in SRX results in the formation of a dimer in the crystal structure. Based on structural conservation we present the SR-GTP:SRX structure as a prototype for conserved interactions in a variety of GTPase regulated targeting events occurring at endomembranes.

Received for publication, November 18, 2005 , and in revised form, January 25, 2006.

The atomic coordinates and structure factors (code 2FH5) have been deposited in the Protein Data Bank, Research Collaboratory for Structural Bioinformatics, Rutgers University, New Brunswick, NJ (http://www.rcsb.org/).

^* This work was supported by the Deutsche Forschungsgemeinschaft (SFB352 and SFB638) and by European Union Network Grant QLK-3CT-2000-00082 to (I. S.). 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 To whom correspondence should be addressed. Tel.: 49-6221-544785; Fax: 49-6221-544790; E-mail: klemens.wild{at}bzh.uni-heidelberg.de.

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

This article has been cited by other articles:

				W. Wen, L. Chen, H. Wu, X. Sun, M. Zhang, and D. K. Banfield Identification of the Yeast R-SNARE Nyv1p as a Novel Longin Domain-containing Protein Mol. Biol. Cell, October 1, 2006; 17(10): 4282 - 4299. [Abstract] [Full Text] [PDF]

				M. Halic, M. Gartmann, O. Schlenker, T. Mielke, M. R. Pool, I. Sinning, and R. Beckmann Signal recognition particle receptor exposes the ribosomal translocon binding site. Science, May 5, 2006; 312(5774): 745 - 747. [Abstract] [Full Text] [PDF]