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

J. Biol. Chem., Vol. 280, Issue 12, 11798-11806, March 25, 2005

This Article Full Text Full Text (PDF) All Versions of this Article: 280/12/11798    most recent M408768200v1 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 Takahashi-Terada, A. Articles by Izui, K. Search for Related Content PubMed PubMed Citation Articles by Takahashi-Terada, A. Articles by Izui, K. Social Bookmarking                      What's this?

Maize Phosphoenolpyruvate Carboxylase

MUTATIONS AT THE PUTATIVE BINDING SITE FOR GLUCOSE 6-PHOSPHATE CAUSED DESENSITIZATION AND ABOLISHED RESPONSIVENESS TO REGULATORY PHOSPHORYLATION^*

Akiko Takahashi-Terada, Masaaki Kotera, Kenta Ohshima, Tsuyoshi Furumoto, Hiroyoshi Matsumura¶, Yasushi Kai¶, and Katsura Izui||

From the Graduate School of Biostudies, Kyoto University, Kitashirakawa, Sakyo-ku, Kyoto 606-8502 and the ^¶Graduate School of Engineering, Osaka University, Suita 565-0871, Japan

Phosphoenolpyruvate carboxylases (PEPC, EC 4.1.1.31) from higher plants are regulated by both allosteric effects and reversible phosphorylation. Previous x-ray crystallographic analysis of Zea mays PEPC has revealed a binding site for sulfate ion, speculated to be the site for an allosteric activator, glucose 6-phosphate (Glc-6-P) (Matsumura, H., Xie, Y., Shirakata, S., Inoue, T., Yoshinaga, T., Ueno, Y., Izui, K., and Kai, Y. (2002) Structure (Lond.) 10, 1721-1730). Because kinetic experiments have also supported this notion, each of the four basic residues (Arg-183, -184, -231, and -372' on the adjacent subunit) located at or near the binding site was replaced by Gln, and the kinetic properties of recombinant mutant enzymes were investigated. Complete desensitization to Glc-6-P was observed for R183Q, R184Q, R183Q/R184Q (double mutant), and R372Q, as was a marked decrease in the sensitivity for R231Q. The heterotropic effect of Glc-6-P on an allosteric inhibitor, L-malate, was also abolished, but sensitivity to Gly, another allosteric activator of monocot PEPC, was essentially not affected, suggesting the distinctness of their binding sites. Considering the kinetic and structural data, Arg-183 and Arg-231 were suggested to be involved directly in the binding with phosphate group of Glc-6-P, and the residues Arg-184 and Arg-372 were thought to be involved in making up the site for Glc-6-P and/or in the transmission of an allosteric regulatory signal. Most unexpectedly, the mutant enzymes had almost lost responsiveness to regulatory phosphorylation at Ser-15. An apparent lack of kinetic competition between the phosphate groups of Glc-6-P and of phospho-Ser at 15 suggested the distinctness of their binding sites. The possible roles of these Arg residues are discussed.

Received for publication, August 2, 2004 , and in revised form, January 21, 2005.

^* This work was supported in part by Grants-in-Aid for Scientific Research (B) from the Ministry of Education, Science, Sports, and Culture of Japan, a grant for the Recombinant Plant Project from the Ministry of Agriculture, Forestry and Fisheries of Japan, and a grant from Ajinomoto Co. (to K. I.). 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.

Supported by the 21st Century COE Program of the Ministry of Education, Culture, Sports, Science and Technology Agency of the Japanese Government.

^|| To whom correspondence should be addressed: Laboratory of Plant Physiology, Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan. Tel.: 81-75-753-6140; Fax: 81-75-753-6470; E-mail: izui{at}kais.kyoto-u.ac.jp.

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

This article has been cited by other articles:

				L. Lejay, J. Wirth, M. Pervent, J. M.-F. Cross, P. Tillard, and A. Gojon Oxidative Pentose Phosphate Pathway-Dependent Sugar Sensing as a Mechanism for Regulation of Root Ion Transporters by Photosynthesis Plant Physiology, April 1, 2008; 146(4): 2036 - 2053. [Abstract] [Full Text] [PDF]

				S. Rao, J. Reiskind, and G. Bowes Light Regulation of the Photosynthetic Phosphoenolpyruvate Carboxylase (PEPC) in Hydrilla verticillata Plant Cell Physiol., September 1, 2006; 47(9): 1206 - 1216. [Abstract] [Full Text] [PDF]

				W. Xu, S. Ahmed, H. Moriyama, and R. Chollet The Importance of the Strictly Conserved, C-terminal Glycine Residue in Phosphoenolpyruvate Carboxylase for Overall Catalysis: MUTAGENESIS AND TRUNCATION OF GLY-961 IN THE SORGHUM C4 LEAF ISOFORM J. Biol. Chem., June 23, 2006; 281(25): 17238 - 17245. [Abstract] [Full Text] [PDF]

				V. Crowley, S. Gennidakis, and W. C. Plaxton In vitro Proteolysis of Phosphoenolpyruvate Carboxylase from Developing Castor Oil Seeds by an Endogenous Thiol Endopeptidase Plant Cell Physiol., November 1, 2005; 46(11): 1855 - 1862. [Abstract] [Full Text] [PDF]