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

J. Biol. Chem., Vol. 275, Issue 46, 35792-35798, November 17, 2000

This Article Full Text Full Text (PDF) All Versions of this Article: 275/46/35792    most recent M006526200v1 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 Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Schepens, I. Articles by Decottignies, P. Search for Related Content PubMed PubMed Citation Articles by Schepens, I. Articles by Decottignies, P. Social Bookmarking                      What's this?

The Role of Active Site Arginines of Sorghum NADP-Malate Dehydrogenase in Thioredoxin-dependent Activation and Activity^*

Isabelle Schepens, Eric Ruelland, Myroslawa Miginiac-Maslow^§, Pierre Le Maréchal^¶, and Paulette Decottignies^¶

From the  Institut de Biotechnologie des Plantes, UMR 8618 CNRS, Université de Paris-Sud, Bâtiment 630 and ^¶ Institut de Biochimie et de Biologie Moléculaire et Cellulaire, UMR 8619, Université de Paris-Sud, Bâtiment 432, Orsay, France

The activation of sorghum NADP-malate dehydrogenase is initiated by thiol/disulfide interchanges with reduced thioredoxin followed by the release of the C-terminal autoinhibitory extension and a structural modification shaping the active site into a high efficiency and high affinity for oxaloacetate conformation. In the present study, the role of the active site arginines in the activation and catalysis was investigated by site-directed mutagenesis and arginyl-specific chemical derivatization using butanedione. Sequence and mass spectrometry analysis were used to identify the chemically modified groups. Taken together, our data reveal the involvement of Arg-134 and Arg-204 in oxaloacetate coordination, suggest an indirect role for Arg-140 in substrate binding and catalysis, and clearly confirm that Arg-87 is implicated in cofactor binding. In contrast with NAD-malate dehydrogenase, no lactate dehydrogenase activity could be promoted by the R134Q mutation. The decreased susceptibility of the activation of the R204K mutant to NADP and its increased sensitivity to the histidine-specific reagent diethylpyrocarbonate indicated that Arg-204 is involved in the locking of the active site. These results are discussed in relation with the recently published NADP-MDH three-dimensional structures and the previously established three-dimensional structures of NAD-malate dehydrogenase and lactate dehydrogenase.

CiteULike

Complore

Connotea

Del.icio.us

Digg

Reddit

Technorati

This article has been cited by other articles:

				P. RONDEAU, C. ROUCH, and G. BESNARD NADP-Malate Dehydrogenase Gene Evolution in Andropogoneae (Poaceae): Gene Duplication Followed by Sub-functionalization Ann. Bot., December 1, 2005; 96(7): 1307 - 1314. [Abstract] [Full Text] [PDF]

				J. V. Moller, G. Lenoir, C. Marchand, C. Montigny, M. le Maire, C. Toyoshima, B. S. Juul, and P. Champeil Calcium Transport by Sarcoplasmic Reticulum Ca2+-ATPase. ROLE OF THE A DOMAIN AND ITS C-TERMINAL LINK WITH THE TRANSMEMBRANE REGION J. Biol. Chem., October 4, 2002; 277(41): 38647 - 38659. [Abstract] [Full Text] [PDF]