Stereoselective Production of Dimethyl-Substituted Carbapenams via Engineered Carbapenem Biosynthesis Enzymes

Stereoselective biocatalysis by crotonase super family enzymes is exemplified by use of engineered 5-carboxymethylproline synthases (CMPSs) for preparation of functionalized 5-carboxymethylproline (5-CMP) derivatives methylated at two positions (i.e., C2/C6, C3/C6, and C5/C6), including products with a quaternary center, from appropriately substituted-amino acid aldehydes anzd C-2 epimeric methylmalonyl-CoA. The enzymatically produced disubstituted 5-CMPs were converted by carbapenam synthetase into methylated bicyclic beta-lactams, which manifestly improved hydrolytic stability compared to the unsubstituted carbapenams. The results highlight the use of modified carbapenem biosynthesis enzymes for production of carbapenams with improved properties.