PROTEIN ENGINEERING

Engineering enzymes to stand alone

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Science  04 Dec 2015:
Vol. 350, Issue 6265, pp. 1218-1219
DOI: 10.1126/science.350.6265.1218-c

Enzymes efficiently synthesize many useful compounds. However, in many cases, their need to associate with other proteins limits their biosynthetic utility outside of cells. Buller et al. used directed evolution (a method of protein engineering that mimics of the process of natural selection) to increase the catalytic activity of the β subunit of the tryptophan synthase complex (TrpB). TrpB makes l-tryptophan from l-serine and indole but is inefficient on its own. Mutations that restored activity to TrpB alone act through the same mechanism as partner protein binding. Both use a mechanism called allostery, in which changes distant from the active site affect enzymatic activity. The standalone TrpB provides a simplified platform to produce noncanonical amino acids.

Proc. Natl. Acad. Sci. U.S.A. 10.1073/pnas.1516401112 (2015).

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