Two Diterpene Synthases for Spiroalbatene and Cembrene A from Allokutzneria albata.

Two bacterial diterpene synthases from the actinomycete Allokutzneria albata were investigated, resulting in the identification of the structurally unprecedented compound spiroalbatene from the first and cembrene A from the second enzyme. Both enzymes were thoroughly investigated in terms of their mechanisms by isotope labeling experiments, site-directed mutagenesis, and variation of the metal cofactors and pH value. For spiroalbatene synthase, the pH- and Mn²⁺ -dependent formation of the side product thunbergol was observed, which is biosynthetically linked to spiroalbatene.