1O0S

Crystal Structure of Ascaris suum Malic Enzyme Complexed with NADH

Summary for 1O0S

• Entry DOI: 10.2210/pdb1o0s/pdb
• Related: 1LLQ
• Descriptor: NAD-dependent malic enzyme, TARTRONATE, 1,4-DIHYDRONICOTINAMIDE ADENINE DINUCLEOTIDE, ... (4 entities in total)
• Functional Keywords: oxidoreductase, oxidative decarboxylase, rossmann fold, malate dehydrogenase, ascaris suum
• Biological source: Ascaris suum (pig roundworm)
• Cellular location: Mitochondrion matrix: P27443
• Total number of polymer chains: 2
• Total formula weight: 138679.78

Authors

Rao, G.S.,Coleman, D.E.,Karsten, W.E.,Cook, P.F.,Harris, B.G. (deposition date: 2003-02-24, release date: 2003-07-22, Last modification date: 2023-08-16)

Primary citation

Rao, G.S.,Coleman, D.E.,Karsten, W.E.,Cook, P.F.,Harris, B.G.
Crystallographic studies on Ascaris suum NAD-malic enzyme bound to reduced cofactor and identification of an effector site.
J.Biol.Chem., 278:38051-38058, 2003

PubMed Abstract: 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.

PubMed: 12853453
DOI: 10.1074/jbc.M305145200

Experimental method

X-RAY DIFFRACTION (2 Å)