Switching on a Nontraditional Enzymatic Base—Deprotonation by Serine in the ent-Kaurene Synthase from Bradyrhizobium japonicum
Terpene synthases often catalyze complex carbocation cascade reactions. It has been previously shown that single-residue switches involving replacement of a key aliphatic residue with serine or threonine can “short-circuit” such reactions that are presumed to act indirectly via dipole stabilization of intermediate carbocations. Here a similar switch was found in the structurally characterized ent-kaurene synthase from Bradyrhizobium japonicum. Application of a recently developed computational approach to terpene synthases, TerDockin, surprisingly indicates direct action of the introduced serine hydroxyl as a catalytic base. Notably, this model suggests an alternative interpretation of previous results and potential routes toward reengineering terpene synthase activity more generally.
This is a manuscript of an article published as Jia, Meirong, Yue Zhang, Justin B. Siegel, Dean J. Tantillo, and Reuben J. Peters. "Switching on a Nontraditional Enzymatic Base–Deprotonation by Serine in the ent-Kaurene Synthase from Bradyrhizobium japonicum." ACS Catalysis (2019). doi: 10.1021/acscatal.9b02783. Posted with permission.