Microbial rhodoquinone biosynthesis proceeds via an atypical RquA-catalyzed amino transfer from S-adenosyl-L-methionine to ubiquinone

Abstract

The RquA protein is required for rhodoquinone biosynthesis; however, its exact function is not yet known. Here, the authors demonstrate that RquA is homologous to SAM-dependent methyltransferases but functions as an aminotransferase using Mn2+ as cofactor to convert ubiquinone to rhodoquinone.