Carbene transfer in a cell

Abstract

Synthetic chemists have long used carbenes to create cyclopropyl groups and to strategically insert carbon into certain bonds. But these highly reactive intermediates haven’t been available in the realm of synthetic biology—until now. Scientists have created Streptomyces albus cells that can biosynthesize azaserine, a natural product and carbene precursor, and they got it to react with styrene also made by the same cellular system. An engineered P450 enzyme catalyzed the cyclopropanation reaction (shown). “The whole process end to end is happening in the cell. You basically are adding glucose on one side and getting a cyclopropanated bioactive compound on the other side,” says Aindrila Mukhopadhyay, an expert in microbial processes at Lawrence Berkeley National Laboratory, and a leader on the project. The synthetic biology system could help researchers create cyclopropanated versions of natural products, says John F. Hartwig, a chemist at the University of California, Berkeley, who also co-led the