| Structural highlights
Function
GMPR2_HUMAN Catalyzes the irreversible NADPH-dependent deamination of GMP to IMP. It functions in the conversion of nucleobase, nucleoside and nucleotide derivatives of G to A nucleotides, and in maintaining the intracellular balance of A and G nucleotides. Plays a role in modulating cellular differentiation.[1] [2]
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
Inosine monophosphate dehydrogenase (IMPDH) and guanosine monophosphate reductase (GMPR) belong to the same structural family, share a common set of catalytic residues and bind the same ligands. The structural and mechanistic features that determine reaction outcome in the IMPDH and GMPR family have not been identified. Here we show that the GMPR reaction uses the same intermediate E-XMP* as IMPDH, but in this reaction the intermediate reacts with ammonia instead of water. A single crystal structure of human GMPR type 2 with IMP and NADPH fortuitously captures three different states, each of which mimics a distinct step in the catalytic cycle of GMPR. The cofactor is found in two conformations: an 'in' conformation poised for hydride transfer and an 'out' conformation in which the cofactor is 6 A from IMP. Mutagenesis along with substrate and cofactor analog experiments demonstrate that the out conformation is required for the deamination of GMP. Remarkably, the cofactor is part of the catalytic machinery that activates ammonia.
Cofactor mobility determines reaction outcome in the IMPDH and GMPR (beta-alpha)(8) barrel enzymes.,Patton GC, Stenmark P, Gollapalli DR, Sevastik R, Kursula P, Flodin S, Schuler H, Swales CT, Eklund H, Himo F, Nordlund P, Hedstrom L Nat Chem Biol. 2011 Oct 30;7(12):950-8. doi: 10.1038/nchembio.693. PMID:22037469[3]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Deng Y, Wang Z, Ying K, Gu S, Ji C, Huang Y, Gu X, Wang Y, Xu Y, Li Y, Xie Y, Mao Y. NADPH-dependent GMP reductase isoenzyme of human (GMPR2). Expression, purification, and kinetic properties. Int J Biochem Cell Biol. 2002 Sep;34(9):1035-50. PMID:12009299
- ↑ Zhang J, Zhang W, Zou D, Chen G, Wan T, Zhang M, Cao X. Cloning and functional characterization of GMPR2, a novel human guanosine monophosphate reductase, which promotes the monocytic differentiation of HL-60 leukemia cells. J Cancer Res Clin Oncol. 2003 Feb;129(2):76-83. Epub 2003 Mar 1. PMID:12669231 doi:http://dx.doi.org/10.1007/s00432-002-0413-7
- ↑ Patton GC, Stenmark P, Gollapalli DR, Sevastik R, Kursula P, Flodin S, Schuler H, Swales CT, Eklund H, Himo F, Nordlund P, Hedstrom L. Cofactor mobility determines reaction outcome in the IMPDH and GMPR (beta-alpha)(8) barrel enzymes. Nat Chem Biol. 2011 Oct 30;7(12):950-8. doi: 10.1038/nchembio.693. PMID:22037469 doi:10.1038/nchembio.693
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