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

J. Biol. Chem., Vol. 283, Issue 22, 15232-15240, May 30, 2008

This Article Full Text Full Text (PDF) Supplemental Data All Versions of this Article: 283/22/15232    most recent M800479200v1 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 Lee, S. Articles by Kim, K. J. PubMed PubMed Citation Articles by Lee, S. Articles by Kim, K. J. Social Bookmarking                      What's this?

Crystal Structure of Escherichia coli MazG, the Regulator of Nutritional Stress Response^*

Sujin Lee, Myung Hee Kim, Beom Sik Kang^¶, Jeong-Sun Kim^||, Ghyung-Hwa Kim, Yeon-Gil Kim, and Kyung Jin Kim¹

From the Pohang Accelerator Laboratory, Pohang University of Science and Technology, Pohang, Kyungbuk 790-784, Korea, the Korea Research Institute of Biosciences and Biotechnology, Yusong, Daejon 305-600, Korea, the ^¶School of Life Science and Biotechnology, Kyungpook National University, Daegu 702-701, Korea, and the ^||Department of Chemistry, Chonnam National University, Gwangju 500-757, Korea

MazG is a nucleoside triphosphate pyrophosphohydrolase that hydrolyzes all canonical nucleoside triphosphates. The mazG gene located downstream from the chromosomal mazEF "addiction module," that mediated programmed cell death in Escherichia coli. MazG activity is inhibited by the MazEF complex both in vivo and in vitro. Enzymatic activity of MazG in vivo affects the cellular level of guanosine 3',5'-bispyrophosphate (ppGpp), synthesized by RelA under amino acid starvation. The reduction of ppGpp, caused by MazG, may extend the period of cell survival under nutritional stress. Here we describe the first crystal structure of active MazG from E. coli, which is composed of two similarly folded globular domains in tandem. Among the two putative catalytic domains, only the C-terminal domain has well ordered active sites and exhibits an NTPase activity. The MazG-ATP complex structure and subsequent mutagenesis studies explain the peculiar active site environment accommodating all eight canonical NTPs as substrates. In vivo nutrient starvation experiments show that the C terminus NTPase activity is responsible for the regulation of bacterial cell survival under nutritional stress.

Received for publication, January 18, 2008

The atomic coordinates and structure factors (codes 3cra and 3crc) 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 funded by the 21C Frontier Microbial Genomics and Application Center Program, Ministry of Science and Technology, Republic of Korea. 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 Table 1 and Figs. 1–4.

¹ To whom correspondence should be addressed. Tel.: 82-54-279-1546; Fax: 82-54-279-1599; E-mail: kkj{at}postech.ac.kr.

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