1KEQ

Crystal Structure of F65A/Y131C Carbonic Anhydrase V, covalently modified with 4-chloromethylimidazole

Summary for 1KEQ

• Entry DOI: 10.2210/pdb1keq/pdb
• Related: 1DMX
• Descriptor: F65A/Y131C-MI Carbonic Anhydrase V, POTASSIUM ION, ZINC ION, ... (6 entities in total)
• Functional Keywords: proton transfer, engineered residue, lyase
• Biological source: Mus musculus (house mouse)
• Total number of polymer chains: 2
• Total formula weight: 57040.04

Authors

Jude, K.M.,Wright, S.K.,Tu, C.,Silverman, D.N.,Viola, R.E.,Christianson, D.W. (deposition date: 2001-11-16, release date: 2002-03-06, Last modification date: 2024-10-30)

Primary citation

Jude, K.M.,Wright, S.K.,Tu, C.,Silverman, D.N.,Viola, R.E.,Christianson, D.W.
Crystal structure of F65A/Y131C-methylimidazole carbonic anhydrase V reveals architectural features of an engineered proton shuttle.
Biochemistry, 41:2485-2491, 2002

PubMed Abstract: 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.

PubMed: 11851394
DOI: 10.1021/bi015808q

Experimental method

X-RAY DIFFRACTION (1.88 Å)