Directed Evolution and Enzyme Libraries

Directed evolution has rapidly emerged as a powerful new tool for altering the properties of an enzyme in a targeted manner. Provided that the desired characteristic can been selected for by means of an analytical screen, it is possible to consider altering a range of properties of a particular enzyme including enantioselectivity, substrate specificity, solvent stability, catalytic turnover and thermal stability. 

In order to broaden the appHcation of CALB to bulky substrates, engineering of the enzyme was undertaken. An in silico library of 2400 CALB variants was constructed and screened by substrate-imprinted docking. Eleven variants were subsequently expressed in Escherichia coU BL21, and tested in the hydrolysis of two branched fatty acids five gave initial increase in activity. The most active variant was taken on for further study [49]. 

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