The Pursuit of a Hydroxylation Switch Uncovers a Key Residue for Various Product Outcomes in the <i>ent</i>-Kaurene Synthase from <i>Bradyrhizobium japonicum</i>

A single residue switch leading to hydroxylation has been identified in <i>ent</i>-kaurene synthases (KSs) from plant gibberellin hormone biosynthesis. In this work, we identified a putative equivalent in the bacterial BjKS from the gibberellin-producing <i>Bradyrhizobium japonicum</i>. Notably, this serves as a key residue that can be varied in concert with a surrounding network to redirect product outcome, with a specificity of up to 94%, providing mechanistic insight into not only BjKS but also (di)terpene synthases more generally.