Directed evolution strategies

For some recent reviews on enzyme modification see (a) Reetz, M.T., Evolution in the test-tube as a means to creat selective biocatalysts. Chimia, 2007,61, 100-103 (b) Sylvestre, J., Chautard, H., Cedrone, E. and Delcourt, M., Directed evolution of biocatalysts. Org. Proc. Res. Dev., 2006, 10, 562-571 (c) Hibbert, E.G. and Dalby, P.A., Directed evolution strategies for improved enzymatic performance. Microb. Cell Fact., 2004, 4, 29 (d) Otten, L.G. and Quax, W.J., Directed evolution selecting today s biocatalysts. Biomol. Eng., 2005, 22, 1-9. 

Figure 6.7 Directed evolution strategy to improve E. coli DERA s stability in the presence of chloroacetaldehyde (ClAA, left) and its productivity in the reaction to monoaldol 7 and lactol 1 (right).

Based on these arguments, we developed the simple directed evolution strategy illustrated in Fig. 1 [2, 6], In comparison to the enzyme performing a function for which it is selected in nature, the new job is performed poorly indeed. Beneficial mutations will be identified during screening the products of... 

Hibbert, E.G. and Dalby, P.A. (2005) Directed evolution strategies for improved enzymatic performance. Microb. Cell Fact., 4, 29. 

Overexpression of these genes enabled growth, but in order to improve the activity of citramalate synthase, directed evolution strategy was used (Kuchner and Arnold 1997). Growth phenotype linked to 2-keto acids (as precursors of amino acids) was used as selection in directed evolution (Connor and Liao 2009). 

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