title: The dimer contact area of sorghum NADP-malate dehydrogenase: role of aspartate 101 in dimer stability and catalytic activity.
abstract: During thioredoxin-mediated activation of chloroplastic NADP-malate dehydrogenase, a homodimeric enzyme, the interaction between subunits is known to be loosened but maintained. A modeling of the 3D structure of the protein identified Asp-101 as being potentially involved in the association between subunits through an electrostatic interaction. Indeed, upon site-directed substitution of Asp-101 by an asparagine, the mutated enzyme behaved mainly as a monomer. The mutation strongly affected the catalytical efficiency of the enzyme. The now available 3D structure of the enzyme shows that Asp-101 is protruding at the dimer interface, interacting with Arg-268 of the neighbouring subunit.
authors.affiliation: Institut de Biotechnologie des Plantes, UMR 8618 CNRS, Bâtiment 630, Université de Paris-Sud, 91405, Orsay, France.
authors.forename: I
authors.initials: I
authors.lastname: Schepens
authors.forename: P
authors.initials: P
authors.lastname: Decottignies
authors.forename: E
authors.initials: E
authors.lastname: Ruelland
authors.forename: K
authors.initials: K
authors.lastname: Johansson
authors.forename: M
authors.initials: M
authors.lastname: Miginiac-Maslow
mesh_terms: D019943:Amino Acid Substitution / Q000235:genetics; D001120:Arginine / Q000378:metabolism; D001224:Aspartic Acid / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites; D015153:Blotting, Western; D002384:Catalysis / Q000187:drug effects; D019281:Dimerization; D004220:Disulfides / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation / Q000187:drug effects; D004795:Enzyme Stability; D007700:Kinetics; D008291:Malate Dehydrogenase / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D050538:Malate Dehydrogenase (NADP+); D008958:Models, Molecular; D008970:Molecular Weight; D009154:Mutation / Q000235:genetics; D006109:Poaceae / Q000201:enzymology*; D020836:Protein Structure, Quaternary; D055672:Static Electricity; D013879:Thioredoxins / Q000494:pharmacology
chemical_list: D004220:Disulfides; D001224:Aspartic Acid; D013879:Thioredoxins; D001120:Arginine; D008291:Malate Dehydrogenase; D050538:Malate Dehydrogenase (NADP+)