Computational redesign of a mononuclear zinc metalloenzyme for organophosphate hydrolysis

TitleComputational redesign of a mononuclear zinc metalloenzyme for organophosphate hydrolysis
Publication TypeJournal Article
Year of Publication2012
AuthorsKhare, S. D., Kipnis Y., Greisen P. J., Takeuchi R., Ashani Y., Goldsmith M., Song Y., Gallaher J. L., Silman I., Leader H., Sussman J. L., Stoddard B. L., Tawfik D. S., & Baker D.
JournalNature chemical biology
Date Published2012 Feb 5
KeywordsPrimary Publication

The ability to redesign enzymes to catalyze noncognate chemical transformations would have wide-ranging applications. We developed a computational method for repurposing the reactivity of metalloenzyme active site functional groups to catalyze new reactions. Using this method, we engineered a zinc-containing mouse adenosine deaminase to catalyze the hydrolysis of a model organophosphate with a catalytic efficiency (k(cat)/K(m)) of ∼10(4) M(-1) s(-1) after directed evolution. In the high-resolution crystal structure of the enzyme, all but one of the designed residues adopt the designed conformation. The designed enzyme efficiently catalyzes the hydrolysis of the R(P) isomer of a coumarinyl analog of the nerve agent cyclosarin, and it shows marked substrate selectivity for coumarinyl leaving groups. Computational redesign of native enzyme active sites complements directed evolution methods and offers a general approach for exploring their untapped catalytic potential for new reactivities.


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