4gik

Crystal Structure of Pseudouridine Monophosphate Glycosidase/Linear R5P Adduct

spinqualitylabelsall models 4gik, resolution 2.19Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4gik is a 3 chain structure with sequence from Escherichia coli. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.187Å Ligands: MN, R5P Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function PSUG_ECOLI Catalyzes the reversible cleavage of pseudouridine 5'-phosphate (PsiMP) to ribose 5-phosphate and uracil. Functions biologically in the cleavage direction, as part of a pseudouridine degradation pathway.[HAMAP-Rule:MF_01876] Publication Abstract from PubMed Pseudouridine (Psi), the most abundant modification in RNA, is synthesized in situ using Psi synthase. Recently, a pathway for the degradation of Psi was described [Preumont, A., Snoussi, K., Stroobant, V., Collet, J. F., and Van Schaftingen, E. (2008) J. Biol. Chem. 283, 25238-25246]. In this pathway, Psi is first converted to Psi 5'-monophosphate (PsiMP) by Psi kinase and then PsiMP is degraded by PsiMP glycosidase to uracil and ribose 5-phosphate. PsiMP glycosidase is the first example of a mechanistically characterized enzyme that cleaves a C-C glycosidic bond. Here we report X-ray crystal structures of Escherichia coli PsiMP glycosidase and a complex of the K166A mutant with PsiMP. We also report the structures of a ring-opened ribose 5-phosphate adduct and a ring-opened ribose PsiMP adduct. These structures provide four snapshots along the reaction coordinate. The structural studies suggested that the reaction utilizes a Lys166 adduct during catalysis. Biochemical and mass spectrometry data further confirmed the existence of a lysine adduct. We used site-directed mutagenesis combined with kinetic analysis to identify roles for specific active site residues. Together, these data suggest that PsiMP glycosidase catalyzes the cleavage of the C-C glycosidic bond through a novel ribose ring-opening mechanism. Pseudouridine monophosphate glycosidase: a new glycosidase mechanism.,Huang S, Mahanta N, Begley TP, Ealick SE Biochemistry. 2012 Nov 13;51(45):9245-55. doi: 10.1021/bi3006829. Epub 2012 Oct, 30. PMID:23066817 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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