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

J. Biol. Chem., Vol. 282, Issue 32, 23473-23481, August 10, 2007

This Article Full Text Full Text (PDF) Supplemental Data All Versions of this Article: 282/32/23473    most recent M703518200v1 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 Schnell, R. Articles by Schneider, G. Search for Related Content PubMed PubMed Citation Articles by Schnell, R. Articles by Schneider, G. Social Bookmarking                      What's this?

Structural Insights into Catalysis and Inhibition of O-Acetylserine Sulfhydrylase from Mycobacterium tuberculosis

CRYSTAL STRUCTURES OF THE ENZYME -AMINOACRYLATE INTERMEDIATE AND AN ENZYME-INHIBITOR COMPLEX^*

Robert Schnell¹, Wulf Oehlmann, Mahavir Singh^¶, and Gunter Schneider²

From the Department of Medical Biochemistry and Biophysics, Karolinska Institutet, S-171 77 Stockholm, Sweden, LIONEX GmbH, Inhoffenstrasse 7, 38124 Braunschweig, Germany and the ^¶Helmholtz Center for Infection Research, Inhoffenstrasse 7, 38124 Braunschweig, Germany

Cysteine biosynthetic genes are up-regulated in the persistent phase of Mycobacterium tuberculosis, and the corresponding enzymes are therefore of interest as potential targets for novel antibacterial agents. cysK1 is one of these genes and has been annotated as coding for an O-acetylserine sulfhydrylase. Recombinant CysK1 is a pyridoxal phosphate (PLP)-dependent enzyme that catalyzes the conversion of O-acetylserine to cysteine. The crystal structure of the enzyme was determined to 1.8Å resolution. CysK1 belongs to the family of fold type II PLP enzymes and is similar in structure to other O-acetylserine sulfhydrylases. We were able to trap the -aminoacrylate reaction intermediate and determine its structure by cryocrystallography. Formation of the aminoacrylate complex is accompanied by a domain rotation resulting in active site closure. The aminoacrylate moiety is bound in the active site via the covalent linkage to the PLP cofactor and by hydrogen bonds of its carboxyl group to several enzyme residues. The catalytic lysine residue is positioned such that it can protonate the C-carbon atom of the aminoacrylate only from the si-face, resulting in the formation of L-cysteine. CysK1 is competitively inhibited by a four-residue peptide derived from the C-terminal of serine acetyl transferase. The crystallographic analysis reveals that the peptide binds to the enzyme active site, suggesting that CysK1 forms an bi-enzyme complex with serine acetyl transferase, in a similar manner to other bacterial and plant O-acetylserine sulfhydrylases. The structure of the enzyme-peptide complex provides a framework for the design of strong binding inhibitors.

Received for publication, April 27, 2007 , and in revised form, May 30, 2007.

The atomic coordinates and structure factors (code 2Q3B, 2Q3D, and 2Q3C) 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 European Commission Contract LSHP-CT-2005-018729. 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 two supplemental figures.

¹ Supported by the David and Astrid Hageléns Foundation.

² To whom correspondence should be addressed: Dept. of Medical Biochemistry and Biophysics, Karolinska Institutet, S-171 77 Stockholm, Sweden. E-mail: Gunter.Schneider{at}ki.se.

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

This article has been cited by other articles:

				S. Kumaran, H. Yi, H. B. Krishnan, and J. M. Jez Assembly of the Cysteine Synthase Complex and the Regulatory Role of Protein-Protein Interactions J. Biol. Chem., April 10, 2009; 284(15): 10268 - 10275. [Abstract] [Full Text] [PDF]

				C. Tanous, O. Soutourina, B. Raynal, M.-F. Hullo, P. Mervelet, A.-M. Gilles, P. Noirot, A. Danchin, P. England, and I. Martin-Verstraete The CymR Regulator in Complex with the Enzyme CysK Controls Cysteine Metabolism in Bacillus subtilis J. Biol. Chem., December 19, 2008; 283(51): 35551 - 35560. [Abstract] [Full Text] [PDF]

				D. Agren, R. Schnell, W. Oehlmann, M. Singh, and G. Schneider Cysteine Synthase (CysM) of Mycobacterium tuberculosis Is an O-Phosphoserine Sulfhydrylase: EVIDENCE FOR AN ALTERNATIVE CYSTEINE BIOSYNTHESIS PATHWAY IN MYCOBACTERIA J. Biol. Chem., November 14, 2008; 283(46): 31567 - 31574. [Abstract] [Full Text] [PDF]

				C. Paige, S. D. Reid, P. C. Hanna, and A. Claiborne The Type III Pantothenate Kinase Encoded by coaX Is Essential for Growth of Bacillus anthracis J. Bacteriol., September 15, 2008; 190(18): 6271 - 6275. [Abstract] [Full Text] [PDF]