Possible Charged Residue Switch for Acylglycerol Selectivity of Lipase MAS1.

The amino acid residues lining the substrate binding pocket play quite an important role during the lipase catalytic process. The conversion of those residues might cause a dramatic change in the lipase properties, such as the substrate selectivity of lipase. In our study, T237 residue sitting on the entrance of the catalytic pocket in lipase MAS1 was important for the catalytic performance. When replacing polar Thr with the positively charged Arg, the synthesis ratio of partial glycerides/triglycerides increases to 6.32 rather than 1.21 of MAS1 wild type (WT), as the substrate ratio of glycerol and fatty acids is 1:3. And the fatty acid preference shifted to long-chain substrates for mutant T237R rather than middle-chain substrates for MAS1 WT. Molecular docking analysis revealed that hydrophobic and side chain properties of Arg might contribute to the change of the MAS1 lipase catalytic performance. This work would pave a way for the accurate rational transformation of the lipases to produce value lipid for industrial application.