4tta | pdb_00004tta

Crystal structure of double mutant E. Coli purine nucleoside phosphorylase with 2 FMC molecules

spinqualitylabelsall models 4tta, resolution 2.00Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4tta is a 6 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 2Å Ligands: FMC, PO4, SO4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function DEOD_ECOLI Cleavage of guanosine or inosine to respective bases and sugar-1-phosphate molecules.[HAMAP-Rule:MF_01627] Publication Abstract from PubMed Purine nucleoside phosphorylase (PNP) catalyses the cleavage of the glycosidic bond of purine nucleosides using phosphate instead of water as a second substrate. PNP from Escherichia coli is a homohexamer, build as a trimer of dimers, and each subunit can be in two conformations, open or closed. This conformational change is induced by the presence of phosphate substrate, and very likely a required step for the catalysis. Closing one active site strongly affects the others, by a yet unclear mechanism and order of events. Kinetic and ligand binding studies show strong negative cooperativity between subunits. Here, for the first time, we managed to monitor the sequence of nucleoside binding to individual subunits in the crystal structures of the wild-type enzyme, showing that first the closed sites, not the open ones, are occupied by the nucleoside. However, two mutations within the active site, Asp204Ala/Arg217Ala, are enough not only to significantly reduce the effectiveness of the enzyme, but also reverse the sequence of the nucleoside binding. In the mutant the open sites, neighbours in a dimer of those in the closed conformation, are occupied as first. This demonstrates how important for the effective catalysis of Escherichia coli PNP is proper subunit cooperation. Crystallographic snapshots of ligand binding to hexameric purine nucleoside phosphorylase and kinetic studies give insight into the mechanism of catalysis.,Stefanic Z, Narczyk M, Mikleusevic G, Kazazic S, Bzowska A, Luic M Sci Rep. 2018 Oct 18;8(1):15427. doi: 10.1038/s41598-018-33723-1. PMID:30337572 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Purine nucleoside phosphorylase 3D structures

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