3ozb | pdb_00003ozb

Crystal Structure of 5'-methylthioinosine phosphorylase from Psedomonas aeruginosa in complex with hypoxanthine

spinqualitylabelsall models 3ozb, resolution 2.80Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3ozb is a 6 chain structure with sequence from Pseae. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: HPA, SO4 Gene: mtnP, PA14_25210 (PSEAE) Activity: S-methyl-5'-thioadenosine phosphorylase, with EC number 2.4.2.28 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [A0A0H2ZBV8_PSEAB] Catalyzes the reversible phosphorylation of S-methyl-5'-thioinosine (MTI) to hypoxanthine and 5-methylthioribose-1-phosphate. Involved in the breakdown of S-methyl-5'-thioadenosine (MTA), a major by-product of polyamine biosynthesis. Catabolism of (MTA) occurs via deamination to MTI and phosphorolysis to hypoxanthine.[HAMAP-Rule:MF_01963] Publication Abstract from PubMed The PA3004 gene of Pseudomonas aeruginosa PAO1 was originally annotated as a 5'-methylthioadenosine phosphorylase (MTAP). However, the PA3004 encoded protein uses 5'-methylthioinosine (MTI) as a preferred substrate and represents the only known example of a specific MTI phosphorylase (MTIP). MTIP does not utilize 5'-methylthioadenosine (MTA). Inosine is a weak substrate with a k(cat)/K(m) value 290-fold less than MTI and is the second best substrate identified. The crystal structure of P. aeruginosa MTIP (PaMTIP) in complex with hypoxanthine was determined to 2.8 A resolution and revealed a 3-fold symmetric homotrimer. The methylthioribose and phosphate binding regions of PaMTIP are similar to MTAPs, and the purine binding region is similar to that of purine nucleoside phosphorylases (PNPs). The catabolism of MTA in P. aeruginosa involves deamination to MTI and phosphorolysis to hypoxanthine (MTA --> MTI --> hypoxanthine). This pathway also exists in Plasmodium falciparum, where the purine nucleoside phosphorylase (PfPNP) acts on both inosine and MTI. Three tight-binding transition state analogue inhibitors of PaMTIP are identified with dissociation constants in the picomolar range. Inhibitor specificity suggests an early dissociative transition state for PaMTIP. Quorum sensing molecules are associated with MTA metabolism in bacterial pathogens suggesting PaMTIP as a potential therapeutic target. Methylthioinosine phosphorylase from Pseudomonas aeruginosa. Structure and annotation of a novel enzyme in quorum sensing.,Guan R, Ho MC, Almo SC, Schramm VL Biochemistry. 2011 Feb 22;50(7):1247-54. Epub 2011 Jan 25. PMID:21197954 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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