Isoafricanol synthase from Streptomyces malaysiensis

Area of Science:

• Microbiology
• Biochemistry
• Genomics

Background:

• Streptomyces species are known for producing diverse secondary metabolites.
• Terpene cyclases are crucial enzymes in the biosynthesis of complex terpenoids.
• The specific role of terpene cyclases in Streptomyces malaysiensis was previously uncharacterized.

Purpose of the Study:

• To identify and characterize terpene cyclase genes in Streptomyces malaysiensis.
• To elucidate the cyclization mechanism of the identified (+)-isoafricanol synthase.
• To investigate the prevalence of homologous enzymes in other Streptomyces genomes.

Main Methods:

• Genome sequencing of Streptomyces malaysiensis DSM 4137.
• Gene cloning and heterologous expression of a terpene cyclase gene.
• Enzymatic assays using isotopically labeled precursors to study the cyclization mechanism.
• Bioinformatic analysis of other Streptomyces genomes to identify homologous genes.

Main Results:

• Four terpene cyclase genes were identified in Streptomyces malaysiensis.
• One gene was characterized as (+)-isoafricanol synthase, responsible for synthesizing (+)-isoafricanol.
• The cyclization mechanism of (+)-isoafricanol synthase was elucidated using isotopic labeling.
• Homologous genes encoding putative (+)-isoafricanol synthases were found in multiple other sequenced Streptomyces species.

Conclusions:

• Streptomyces malaysiensis possesses a dedicated (+)-isoafricanol synthase.
• The study provides insights into the biosynthetic pathway of (+)-isoafricanol.
• The widespread presence of homologous genes suggests a conserved role for (+)-isoafricanol biosynthesis in Streptomyces.