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

Rafaella Stepanova, Hayato Inagi, Kei Sugawara, Kazuya Asada, Tomoyuki Nishi, Daijiro Ueda, Yoko Yasuno, Tetsuro Shinada, Kunio Miki, Masahiro Fujihashi, Tsutomu Sato

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)


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 (C20-C35) prenyl-diphosphates as substrates and no amino acid sequence homology with known TS. Conversion of long prenyl-diphosphates such as heptaprenyl-diphosphate (C35) is unusual and has never been reported for Class I and II enzymes. Therefore, the characterization of Class IB enzymes is crucial to understand the reaction mechanism of the extensive terpene synthesis. Here, we report the crystal structure bound with a substrate surrogate and biochemical analysis of a Class IB TS, using the enzyme from Bacillus alcalophilus (BalTS). The structure analysis revealed that the diphosphate part of the substrate is located around the two characteristic Asp-rich motifs, and the hydrophobic tail is accommodated in a unique hydrophobic long tunnel, where the C35 prenyl-diphosphate, the longest substrate of BalTS, can be accepted. Biochemical analyses of BalTS showed that the enzymatic property, such as Mg2+ dependency, is similar to those of Class I enzymes. In addition, a new cyclic terpene was identified from BalTS reaction products. Mutational analysis revealed that five of the six Asp residues in the Asp-rich motifs and two His residues are essential for the formation of the cyclic skeleton. These results provided a clue to consider the application of the unusual large terpene synthesis by Class IB enzymes.

Original languageEnglish
Pages (from-to)1517-1525
Number of pages9
JournalACS Chemical Biology
Issue number6
Publication statusPublished - Jun 19 2020
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Molecular Medicine


Dive into the research topics of 'Characterization of Class IB Terpene Synthase: The First Crystal Structure Bound with a Substrate Surrogate'. Together they form a unique fingerprint.

Cite this