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

J. Biol. Chem., Vol. 280, Issue 50, 41465-41471, December 16, 2005

This Article Full Text Full Text (PDF) All Versions of this Article: 280/50/41465    most recent M507077200v1 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 Sivaraja, V. Articles by Yu, C. Search for Related Content PubMed PubMed Citation Articles by Sivaraja, V. Articles by Yu, C. Social Bookmarking                      What's this?

Three-Dimensional Solution Structures of the Chromodomains of cpSRP43^*

Vaithiyalingam Sivaraja, Thallapuranam Krishnaswamy Suresh Kumar, Philominathan Sagaya Theresa Leena, An-ni Chang, Chitturi Vidya, Robyn L. Goforth¶, Dakshinamurthy Rajalingam, Kannan Arvind, Jiang-Liang Ye||, Jonathan Chou**, Ralph Henry¶, and Chin Yu1

From the Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, Arkansas 72701, Department of Chemistry, National Tsing Hua University, Hsinchu, Taiwan 30043, ^¶Department of Biological Sciences, University of Arkansas, Fayetteville, Arkansas 72701, ^||Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Fujian 361005, China, and ^**Gentara Corporation, Malvern, Pennsylvania 19355

Chloroplasts contain a unique signal recognition particle (cpSRP). Unlike the cytoplasmic forms, the cpSRP lacks RNA but contains a conserved 54-kDa GTPase and a novel 43-kDa subunit (cpSRP43). Recently, three functionally distinct chromodomains (CDs) have been identified in cpSRP43. In the present study, we report the three-dimensional solution structures of the three CDs (CD1, CD2, and CD3) using a variety of triple resonance NMR experiments. The structure of CD1 consists of a triple-stranded -sheet segment. The C-terminal helical segment typically found in the nuclear chromodomains is absent in CD1. The secondary structural elements in CD2 and CD3 include a triple-stranded antiparallel -sheet and a C-terminal helix. Interestingly, the orientation of the C-terminal helix is significantly different in the structures of CD2 and CD3. Critical comparison of the structures of the chromodomains of cpSRP43 with those found in nuclear chromodomain proteins revealed that the diverse protein-protein interactions mediated by the CDs appear to stem from the differences that exist in the surface charge potentials of each CD. Results of isothermal titration calorimetry experiments confirmed that only CD2 is involved in binding to cpSRP54. The negatively charged C-terminal helix in CD2 possibly plays a crucial role in the cpSRP54-cpSRP43 interaction.

Received for publication, June 29, 2005 , and in revised form, September 22, 2005.

The atomic coordinates and structure factors (code 1X32, 1X3Q, 1X3P) have been deposited in the Protein Data Bank, Research Collaboratory for Structural Bioinformatics, Rutgers University, New Brunswick, NJ (http://www.rcsb.org/).

Resonance assignments of CDs have been deposited in the BioMagRresBank under accession codes 6589 (CD1), 6592 (CD2), and 6593 (CD3).

^* This work was supported by U. S. Department of Energy Grant BR15569, National Center for Research Resources Centers of Biomedical Research Excellence Grant 1 P20, National Institutes of Health, the National Science Council of Taiwan, and the Arkansas Bioscience Institute. 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: Dept. of Chemistry & Biochemistry, University of Arkansas, Chem. 101, Fayetteville, AR 72701. Tel.: 479-575-2724; Fax: 479-575-4049; E-mail: cyu{at}uark.edu.

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

This article has been cited by other articles:

				K. F. Stengel, I. Holdermann, P. Cain, C. Robinson, K. Wild, and I. Sinning Structural Basis for Specific Substrate Recognition by the Chloroplast Signal Recognition Particle Protein cpSRP43 Science, July 11, 2008; 321(5886): 253 - 256. [Abstract] [Full Text] [PDF]