[ODP10] 3. Physiology / Structural biology -a. Metabolism, biosynthesis and metabolome

[ODP-042] Identification and functional analysis of a new type of Z,E-mixed prenyl reductase from mycobacteria

Tohru Abe^1,2,3, Mariko Hakamata², Akihito Nishiyama², Yoshitaka Tateishi², Sohkichi Matsumoto², Hisashi Hemmi³, Daijiro Ueda¹, Tsutomu Sato¹ (¹Grad. Sch., Sci. Technol., Niigata Univ., ²Dept. Bacteriol., Sch. Med., Niigata Univ., ³Grad. Sch., Bioagricultural Sci., Nagoya Univ.)

Isoprenoid with reduced Z,E-mixed prenyl groups have been found in a wide range of organisms. As an enzyme that reduces Z,E-mixed prenyl groups, only polyprenol reductases (PR-Dol) involved in dolichol biosynthesis have been identified to date. Although C₃₅-isoprenoids with reduced Z,E-mixed prenyl groups have also been found in mycobacteria, Z,E-mixed heptaprenyl reductase (HepR) has been unidentified. In this study, in vitro enzymatic assay and in vivo repression analysis using CRISPR interference revealed that the GGR homolog, which reacts with an all-E prenyl group as a substrate, is HepR. Therefore, it was demonstrated that some GGR homologs function as Z,E-mixed prenyl reductase. This is the first identification of a new type of Z,E-mixed prenyl reductase that has no sequence homology with PR-Dol. The substrate specificity of HepR was significantly different from that of GGR, suggesting that HepR has a new recognition site for substrate. The BLAST search revealed that HepR homologs are widely distributed in mycobacterial species. Analysis of lipid components revealed that HepR metabolites are also produced in pathogens such as Mycobacteroides abscessus for the first time. Our results will provide important insights not only for the discovery of new reduced Z,E-mixed isoprenoids, but also for the elucidation of new physiological functions of reduced isoprenoids in vivo.