3b7i

Crystal structure of the S228A mutant of the aminopeptidase from Vibrio proteolyticus in complex with leucine phosphonic acid

spinqualitylabelsall models 3b7i, resolution 1.75Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3b7i is a 1 chain structure with sequence from Vibrio proteolyticus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.75Å Ligands: K, LEU, NA, PLU, SCN, ZN Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function AMPX_VIBPR 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 The chemical properties of zinc make it an ideal metal to study the role of coordination strain in enzymatic rate enhancement. The zinc ion and the protein residues that are bound directly to the zinc ion represent a functional charge/dipole complex, and polarization of this complex, which translates to coordination distortion, may tune electrophilicity, and hence, reactivity. Conserved protein residues outside of the charge/dipole complex, such as second-shell residues, may play a role in supporting the electronic strain produced as a consequence of functional polarization. To test the correlation between charge/dipole polarity and ligand binding affinity, structure-function studies were carried out on the dizinc aminopeptidase from Vibrio proteolyticus. Alanine substitutions of S228 and M180 resulted in catalytically diminished enzymes whose crystal structures show very little change in the positions of the metal ions and the protein residues. However, more detailed inspections of the crystal structures show small positional changes that account for differences in the zinc ion coordination geometry. Measurements of the binding affinity of leucine phosphonic acid, a transition state analogue, and leucine, a product, show a correlation between coordination geometry and ligand binding affinity. These results suggest that the coordination number and polarity may tune the electrophilicity of zinc. This may have provided the evolving enzyme with the ability to discriminate between reaction coordinate species. Zinc coordination geometry and ligand binding affinity: the structural and kinetic analysis of the second-shell serine 228 residue and the methionine 180 residue of the aminopeptidase from Vibrio proteolyticus.,Ataie NJ, Hoang QQ, Zahniser MP, Tu Y, Milne A, Petsko GA, Ringe D Biochemistry. 2008 Jul 22;47(29):7673-83. Epub 2008 Jun 25. PMID:18576673 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Aminopeptidase 3D structures

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