1keq
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Crystal Structure of F65A/Y131C Carbonic Anhydrase V, covalently modified with 4-chloromethylimidazole
OverviewOverview
The crystal structure of F65A/Y131C murine alpha-carbonic anhydrase V, (CAV), covalently modified at cysteine residues with, 4-chloromethylimidazole, is reported at 1.88 A resolution. This, modification introduces a methylimidazole (MI) group at residue C131 in, the active site with important consequences. F65A/Y131C-MI CAV exhibits an, up to 3-fold enhancement of catalytic activity over that of wild-type CAV, [Earnhardt, J. N., Wright, S. K., Qian, M., Tu, C., Laipis, P. J., Viola, R. E., and Silverman, D. N. (1999) Arch. Biochem. Biophys. 361, 264-270]., In this modified CAV variant, C131-MI acts as a proton shuttle, facilitating the deprotonation of a zinc-bound water molecule to, regenerate the nucleophilic zinc-bound hydroxide ion. A network of three, hydrogen-bonded water molecules, across which proton transfer likely, proceeds, bridges the zinc-bound water molecule and the C131-MI imidazole, group. The structure of F65A/Y131C-MI CAV is compared to structures of, Y64H/F65A murine CAV, wild-type human alpha-carbonic anhydrase II, and the, gamma-carbonic anhydrase from Methanosarcina thermophilain an effort to, outline common features of catalytic proton shuttles.
About this StructureAbout this Structure
1KEQ is a Single protein structure of sequence from Mus musculus with K, ZN, 4MZ and ACY as ligands. Active as Carbonate dehydratase, with EC number 4.2.1.1 Full crystallographic information is available from OCA.
ReferenceReference
Crystal structure of F65A/Y131C-methylimidazole carbonic anhydrase V reveals architectural features of an engineered proton shuttle., Jude KM, Wright SK, Tu C, Silverman DN, Viola RE, Christianson DW, Biochemistry. 2002 Feb 26;41(8):2485-91. PMID:11851394
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