Molecular mechanism for the regulation of human mitochondrial NAD(P)+-dependent malic enzyme by ATP and fumarate.
The regulation of human mitochondrial NAD(P)+-dependent malic enzyme (m-NAD-ME) by ATP and fumarate may be crucial for the metabolism of glutamine for energy production in rapidly proliferating tissues and tumors. Here we report the crystal structure at 2.2 A resolution of m-NAD-ME in complex with ATP, Mn2+, tartronate, and fumarate. Our structural, kinetic, and mutagenesis studies reveal unexpectedly that ATP is an active-site inhibitor of the enzyme, despite the presence of an exo binding site. The structure also reveals the allosteric binding site for fumarate in the dimer interface. Mutations in this binding site abolished the activating effects of fumarate. Comparison to the structure in the absence of fumarate indicates a possible molecular mechanism for the allosteric function of this compound.
Department of Biological Sciences, Columbia University, New York, New York 10027, USA.
Zhiru
Z
Yang
Charles W
CW
Lanks
Liang
L
Tong
D000255:Adenosine Triphosphate / Q000737:chemistry*; D000495:Allosteric Site; D000595:Amino Acid Sequence; D001665:Binding Sites; D002413:Cations, Divalent; D018360:Crystallography, X-Ray; D005650:Fumarates / Q000737:chemistry*; D006801:Humans; D007700:Kinetics; D008291:Malate Dehydrogenase / Q000037:antagonists & inhibitors / Q000737:chemistry*; D008345:Manganese / Q000737:chemistry; D008928:Mitochondria / Q000737:chemistry*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation; D013646:Tartronates / Q000737:chemistry
D002413:Cations, Divalent; D005650:Fumarates; D013646:Tartronates; D008345:Manganese; C032005:fumaric acid; D000255:Adenosine Triphosphate; D008291:Malate Dehydrogenase; C031917:malate dehydrogenase (oxaloacetate-decarboxylating) (NADP+)