Crystal Structure of F65A/Y131C-Methylimidazole Carbonic Anhydrase V Reveals Architectural Features of an Engineered Proton Shuttle
| Autor: | Kevin Jude, David N. Silverman, Chingkuang Tu, D.W. Christianson, Ronald E. Viola, S.K. Wright |
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| Rok vydání: | 2002 |
| Předmět: |
biology
Protein Conformation Stereochemistry Inorganic chemistry Imidazoles Active site Crystallography X-Ray Protein Engineering Lyase Biochemistry Carbonic Anhydrase V Mice chemistry.chemical_compound Protein structure Deprotonation chemistry Covalent bond Carbonic anhydrase cardiovascular system biology.protein Animals Imidazole Cysteine |
| Zdroj: | Biochemistry. 41:2485-2491 |
| ISSN: | 1520-4995 0006-2960 |
| DOI: | 10.1021/bi015808q |
| Popis: | 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. |
| Databáze: | OpenAIRE |
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