Serine 105 Is Not Essential for Catalytic Activities of Candida antarctica Lipase B: Creation of Thio-CAL B by Iterative Saturation Mutagenesis

摘要

@@The best-known catalytic mechanism of lipases or proteases use the classical Ser/His/Asp catalytic, where serine is the nucleophile, histidine is the general base and acid, and the aspartate helps orient the histidine residue and neutralize the charge that develops on the histidine during the transition states. In this mechanism, serine is necessary for the catalytic activity, while His and Asp sometimes are changed in nature. Such variations exist in a variety of "non-classical" serine enzyme, using the mechanism of the triads Ser/His/Glu, Ser/His/His, and Ser/Glu/Asp, and also the dyads Ser/Lys and Ser/His.