Substitution of Val72 residue alters the enantioselectivity and activity of Penicillium expansum lipase

Abstract

Error-prone PCR was used to create more active or enantioselective variants of Penicillium expansum lipase (PEL). A variant with a valine to glycine substitution at residue 72 in the lid structure exhibited higher activity and enantioselectivity than those of wild-type PEL. Site-directed saturation mutagenesis was used to explore the sequence-function relationship and the substitution of Val72 of P. expansum lipase changed both catalytic activity and enantioselectivity greatly. The variant V72A, displayed a highest enantioselectivity enhanced to about twofold for the resolution of (R, S)-naproxen (E value increased from 104 to 200.7 for wild-type PEL and V72A variant, respectively). In comparison to PEL, the variant V72A showed a remarkable increase in specific activity towards p-nitrophenyl palmitate (11- and 4-fold increase at 25 and 35 °C, respectively) whereas it had a decreased thermostability. The results suggest that the enantioselective variant V72A could be used for the production of pharmaceutical drugs such as enantiomerically pure (S)-naproxen and the residue Val 72 of P. expansum lipase plays a significant role in the enantioselectivity and activity of this enantioselective lipase.