Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, P.O. Box 30, 420111, Kazan, Russia.
Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, P.O. Box 30, 420111, Kazan, Russia.
Phytochemistry. 2022 Mar;195:113051. doi: 10.1016/j.phytochem.2021.113051. Epub 2021 Dec 8.
Nonclassical P450s of the CYP74 family catalyse the secondary conversions of fatty acid hydroperoxides to bioactive oxylipins in plants. The model organism, spikemoss Selaginella moellendorffii Hieron, possesses at least ten CYP74 genes of novel J, K, L, and M subfamilies. The cloning of three CYP74L genes and catalytic properties of recombinant proteins are described in the present work. The CYP74L1 possessed mainly hydroperoxide lyase (HPL) activity towards the 13(S)-hydroperoxide of α-linolenic acids (13-HPOT) and nearly equal HPL and allene oxide synthase (AOS) activities towards the 13(S)-hydroperoxide of linoleic acids (13-HPOD). The 9-hydroperoxides were poor substrates for CYP74L1 and led to the production of mainly the α-ketols (AOS products) and minorities of HPL and epoxyalcohol synthase (EAS) products. The CYP74L2 possessed the AOS activity towards all tested hydroperoxides. CYP74L3 possessed low HPL/EAS activity. Besides, the aerial parts of S. moellendorffii plants possessed complex oxylipins patterns including divinyl ethers, epoxyalcohols, and 12-oxo-phytodienoic acid. Characterization of the CYP74L enzymes and oxylipin pattern updates the knowledge on the complex oxylipin biosynthetic machinery in the surviving oldest taxa of vascular plants.
非经典 P450s 的 CYP74 家族催化脂肪酸氢过氧化物的次要转化为植物中的生物活性氧脂素。模式生物，卷柏 Selaginella moellendorffii Hieron，至少拥有十个 CYP74 基因的新型 J、K、L 和 M 亚家族。本工作描述了三个 CYP74L 基因的克隆和重组蛋白的催化特性。CYP74L1 对α-亚麻酸的 13(S)-氢过氧化物（13-HPOT）主要具有氢过氧化物裂合酶（HPL）活性，对亚油酸的 13(S)-氢过氧化物（13-HPOD）几乎具有相同的 HPL 和丙烯氧化物合酶（AOS）活性。9-氢过氧化物是 CYP74L1 的较差底物，主要导致生成 α-酮醇（AOS 产物）和较少的 HPL 和环氧化物合酶（EAS）产物。CYP74L2 对所有测试的氢过氧化物都具有 AOS 活性。CYP74L3 具有低的 HPL/EAS 活性。此外，卷柏植物的地上部分具有复杂的氧脂素模式，包括二乙烯基醚、环氧化物和 12-氧-植物二烯酸。CYP74L 酶和氧脂素模式的表征更新了对现存最古老的维管植物类群中复杂的氧脂素生物合成机制的认识。
