1o0s
From Proteopedia
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Crystal Structure of Ascaris suum Malic Enzyme Complexed with NADH
Overview
The crystal structure of the mitochondrial NAD-malic enzyme from Ascaris, suum, in a quaternary complex with NADH, tartronate, and magnesium has, been determined to 2.0-A resolution. The structure closely resembles the, previously determined structure of the same enzyme in binary complex with, NAD. However, a significant difference is observed within the, coenzyme-binding pocket of the active site with the nicotinamide ring of, NADH molecule rotating by 198 degrees over the C-1-N-1 bond into the, active site without causing significant movement of the other catalytic, residues. The implications of this conformational change in the, nicotinamide ring to the catalytic mechanism are discussed. The structure, also reveals a binding pocket for the divalent metal ion in the active, site and a binding site for tartronate located in a highly positively, charged environment within the subunit interface that is distinct from the, active site. The tartronate binding site, presumably an allosteric site, for the activator fumarate, shows striking similarities and differences, with the activator site of the human NAD-malic enzyme that has been, reported recently. Thus, the structure provides additional insights into, the catalytic as well as the allosteric mechanisms of the enzyme.
About this Structure
1O0S is a Single protein structure of sequence from Ascaris suum with TTN and NAI as ligands. Active as Malate dehydrogenase (oxaloacetate-decarboxylating), with EC number 1.1.1.38 Full crystallographic information is available from OCA.
Reference
Crystallographic studies on Ascaris suum NAD-malic enzyme bound to reduced cofactor and identification of an effector site., Rao GS, Coleman DE, Karsten WE, Cook PF, Harris BG, J Biol Chem. 2003 Sep 26;278(39):38051-8. Epub 2003 Jul 9. PMID:12853453
Page seeded by OCA on Tue Nov 20 22:42:55 2007
