Characterization of Class IB Terpene Synthase: The First Crystal Structure Bound with a Substrate Surrogate.

Terpene synthases (TS) are classified into two broad types, Class I and II, based on the chemical strategy for initial carbocation formation and motif sequences of the catalytic site. We have recently identified a new class of enzymes, Class IB, showing the acceptability of long (C-C) prenyl-diphosphates as substrates and no amino acid sequence homology with known TS. Conversion of long prenyl-diphosphates such as heptaprenyl-diphosphate (C) is unusual and has never been reported for Class I and II enzymes.