Molecular characterization of a moss isoprene synthase provides insight into its evolution

• Published in: FEBS letters Vol. 597; no. 16; pp. 2133 - 2142
• Main Authors: Kawakami, Tetsuya, Miyazaki, Sho, Kawaide, Hiroshi
• Format: Journal Article
• Language: English
• Published: England 01.08.2023
• Subjects: bryophyte; copalyl diphosphate; isoprene synthase; Physcomitrium patens; volatile organic compounds; isoprene synthase; bryophyte; Physcomitrium patens; copalyl diphosphate; volatile organic compounds
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1002/1873-3468.14691

This is the first report on the molecular characterization of isoprene synthase (ISPS) from the moss Calohypnum plumiforme. After isoprene emission from C. plumiforme was confirmed, the cDNA encoding C. plumiforme ISPS (CpISPS) was narrowed down using a genome database associated with protein structure prediction, and a CpISPS gene was identified. The recombinant CpISPS, produced in Escherichia coli, converted dimethylallyl diphosphate to isoprene. Phylogenetic analysis indicated similarity between the amino acid sequences of CpISPS and moss diterpene cyclases (DTCs) but not ISPSs of higher plants, implying that CpISPS is derived from moss DTCs and is evolutionarily unrelated to canonical ISPSs of higher plants. CpISPS is a novel class I cyclase of the terpene synthase‐c subfamily harboring αβ domains. This study will help further study of isoprene biosynthesis and the physiological functions of isoprene in mosses. We performed a molecular characterization of isoprene synthase (ISPS) in the isoprene‐emitting moss Calohypnum plumiforme. The enzyme structure was predicted using AlphaFold2, and a candidate ISPS was found. The cDNA encoding ISPS in C. plumiforme (CpISPS) was recombinantly expressed in Escherichia coli, and the purified enzyme was confirmed to produce isoprene. Further characterization indicated that the origin of CpISPS may be a bifunctional diterpene synthase and is different from that of ISPSs in higher plants.