2i65
From Proteopedia
Structural Basis for the Mechanistic Understanding Human CD38 Controlled Multiple Catalysis
Structural highlights
FunctionCD38_HUMAN Synthesizes cyclic ADP-ribose, a second messenger for glucose-induced insulin secretion. Also has cADPr hydrolase activity. Also moonlights as a receptor in cells of the immune system. Evolutionary ConservationCheck, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe enzymatic cleavage of the nicotinamide-glycosidic bond on nicotinamide adenine dinucleotide (NAD(+)) has been proposed to go through an oxocarbenium ion-like transition state. Because of the instability of the ionic intermediate, there has been no structural report on such a transient reactive species. Human CD38 is an ectoenzyme that can use NAD(+) to synthesize two calcium-mobilizing molecules. By using NAD(+) and a surrogate substrate, NGD(+), we captured and determined crystal structures of the enzyme complexed with an intermediate, a substrate, and a product along the reaction pathway. Our results showed that the intermediate is stabilized by polar interactions with the catalytic residue Glu(226) rather than by a covalent linkage. The polar interactions between Glu(226) and the substrate 2',3'-OH groups are essential for initiating catalysis. Ser(193) was demonstrated to have a regulative role during catalysis and is likely to be involved in intermediate stabilization. In addition, a product inhibition effect by ADP-ribose (through the reorientation of the product) or GDP-ribose (through the formation of a covalently linked GDP-ribose dimer) was observed. These structural data provide insights into the understanding of multiple catalysis and clues for drug design. Structural basis for the mechanistic understanding of human CD38-controlled multiple catalysis.,Liu Q, Kriksunov IA, Graeff R, Munshi C, Lee HC, Hao Q J Biol Chem. 2006 Oct 27;281(43):32861-9. Epub 2006 Sep 2. PMID:16951430[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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Categories: Homo sapiens | Large Structures | Graeff R | Hao Q | Kriksunov IA | Lee HC | Liu Q | Munshi C