| Abstract: | Bacteriohopanepolyols are a group of triterpenoids that play important roles in regulating bacterial cell membrane function. As an intermediate in bacteriohopanepolyol biosynthesis, adenosylhopane production is related to a putative Fe‐S protein HpnH, but the exact role of this enzyme remains unsolved. Here we report characterization of HpnH as a novel radical S‐adenosylmethionine (SAM) superfamily enzyme. In contrast to almost all the members in the superfamily, HpnH does not initiate the reaction by a hydrogen atom abstraction process. Instead, it catalyzes the adenosylation of hopene via a radical addition reaction to produce adenosylhopane, representing the second example of radical SAM‐dependent adenosylation involved in natural product biosynthesis. |
