Identification and functional analysis of a new type of Z,E-mixed prenyl reductase from mycobacteria
Identification and functional analysis of a new type of Z,E-mixed prenyl reductase from mycobacteria
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DOI：
10.1111/febs.16412
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发表时间：
2022-03-10
期刊：
影响因子：
5.4
通讯作者：
Sato, Tsutomu
中科院分区：
文献类型：
--
作者：
Abe, Tohru;Hakamata, Mariko;Sato, Tsutomu
具有减少的 Z,E-混合异戊二烯基团的类异戊二烯存在于多种生物体中。迄今为止，只有参与多萜醇生物合成的聚异戊二烯醇还原酶（PR-Dol）被鉴定为能够还原Z，E-混合异戊二烯基团的酶。尽管在分枝杆菌中发现了具有还原的 Z,E-混合异戊二烯基团的 C-35-类异戊二烯，但 Z,E-混合庚烯基还原酶 (HepR) 仍未得到鉴定。本研究对HepR进行了鉴定和功能分析。在范巴氏分枝杆菌基因组中未检测到 PR-Dol 同源基因。然而，基因组中编码了香叶基香叶基还原酶（GGR）的同源物，它与全E异戊烯基基团作为底物发生反应；因此，我们将其作为 HepR 候选者进行分析。体外酶测定和体内基因抑制分析鉴定出GGR同源物为HepR，并揭示HepR催化Z,E-混合庚烯基二磷酸中omega-和E-异戊二烯单位的还原，而C-35-类异戊二烯主要以E,E,E-香叶基香叶基二磷酸作为前体生物合成。因此，证明了Z，E-混合异戊二烯还原酶家族存在于GGR同系物中。据我们所知，这是首次鉴定出与 PR-Dol 没有序列同源性的新型 Z,E-混合异戊二烯还原酶。 HepR的底物特异性与GGR显着不同，表明它是一种新酶。 HepR 同源物广泛分布于分枝杆菌基因组中，脂质分析表明许多菌株，包括致病菌种，都产生 HepR 代谢物。这种新酶的发现将促进Z,E-混合类异戊二烯的进一步研究。
Isoprenoids with reduced Z,E-mixed prenyl groups are found in various organisms. To date, only polyprenol reductases (PR-Dol) involved in dolichol biosynthesis have been identified as enzymes capable of reducing Z,E-mixed prenyl groups. Although C-35-isoprenoids with reduced Z,E-mixed prenyl groups are found in mycobacteria, Z,E-mixed heptaprenyl reductase (HepR) remains unidentified. In the present study, the identification and functional analysis of HepR was performed. No PR-Dol homolog gene was detected in the genome of Mycolicibacterium vanbaalenii. However, a homolog of geranylgeranyl reductase (GGR), which reacts with an all-E prenyl group as a substrate, was encoded in the genome; thus, we analyzed it as a HepR candidate. In vitro enzymatic assay and in vivo gene suppression analysis identified the GGR homolog as HepR and revealed that HepR catalyzes the reduction of omega- and E- prenyl units in Z,E-mixed heptaprenyl diphosphates, and C-35-isoprenoids are mainly biosynthesized using E,E,E-geranylgeranyl diphosphate as a precursor. Thus, it was demonstrated that the Z,E-mixed prenyl reductase family exists in the GGR homologs. To the best of our knowledge, this is the first identification of a new type of Z,E-mixed prenyl reductase with no sequence homology to PR-Dol. The substrate specificity of HepR significantly differed from that of GGR, suggesting that it is a new enzyme. HepR homologs are widely distributed in mycobacterial genomes, and lipid analysis suggests that many strains, including pathogenic species, produce HepR metabolites. The discovery of this new enzyme will promote further research on Z,E-mixed isoprenoids.