5too

Crystal structure of alkaline phosphatase PafA T79S, N100A, K162A, R164A mutant

spinqualitylabelsall models 5too, resolution 2.03Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 5too is a 1 chain structure with sequence from Elizabethkingia meningoseptica. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.031Å Ligands: CL, ZN Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function ALPH_ELIME Publication Abstract from PubMed Members of enzyme superfamilies specialize in different reactions but often exhibit catalytic promiscuity for one anothers reactions, consistent with catalytic promiscuity as an important driver in the evolution of new enzymes. Wanting to understand how catalytic promiscuity and other factors may influence evolution across a superfamily, we turned to the well-studied Alkaline Phosphatase (AP) superfamily, comparing three of its members-two evolutionarily distinct phosphatases and a phosphodiesterase. We mutated distinguishing active-site residues to generate enzymes that had a common Zn2+ bimetallo core, but little sequence similarity and different auxiliary domains. We then tested the catalytic capabilities of these pruned enzymes with a series of substrates. A substantial rate enhancement of ~1011-fold for both phosphate mono- and diester hydrolysis by each enzyme indicated that the Zn2+ bimetallo core is an effective mono/di-esterase generalist and that the bimetallo cores were not evolutionarily tuned to prefer their cognate reactions. In contrast, our pruned enzymes were ineffective sulfatases, and this limited promiscuity may have provided a driving force for founding the distinct one-metal-ion branch that contains all known AP superfamily sulfatases. Finally, our pruned enzymes exhibited 107-108 fold phosphotriesterase rate enhancements, despite absence of such enzymes within the AP superfamily. We speculate that the superfamily active site architecture involved in nucleophile positioning prevents accommodation of the additional triester substituent. Overall, we suggest that catalytic promiscuity and the ease or difficulty of remodeling and building onto existing protein scaffolds have greatly influenced the course of enzyme evolution and will provide lessons for engineering new enzymes. Differential Catalytic Promiscuity of the Alkaline Phosphatase Superfamily Bimetallo Core Reveals Mechanistic Features Underlying Enzyme Evolution.,Sunden F, AlSadhan I, Lyubimov A, Doukov T, Swan J, Herschlag D J Biol Chem. 2017 Oct 25. pii: jbc.M117.788240. doi: 10.1074/jbc.M117.788240. PMID:29070681 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Alkaline phosphatase 3D structures

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