Maeda Isamu, Inaba Atsushi, Koike Hiroyuki, Yoneyama Koichi, Ueda Shunsaku, Yoshida Kazuyuki
Department of Applied Biochemistry, Faculty of Agriculture; and Weed Science Center, Utsunomiya University, 350 Mine-machi, Utsunomiya 321-8505, Japan.
J Biochem. 2013 Nov;154(5):449-54. doi: 10.1093/jb/mvt075. Epub 2013 Aug 13.
Carotenoid cleavage oxygenases catalyse formation of apocarotenoids and the precursors of phytohormones, abscisic acid and strigolactones through oxidative cleavage at specific double bonds of carotenoids. A gene encoding a presumed bacterial oxygenase homologous to lignostilbene-α,β-dioxygenases has been found in the genome of Rhodopseudomonas palustris. By analysing apocarotenoids in recombinant Escherichia coli strains, it was found that the presumed oxygenase catalyses the 15,15' double bond cleavage of lycopene and neurosporene. Cell lysate containing the recombinant protein cleaved all-trans-β-apo-8'-carotenal at the 15,15' double bond into retinal and apo-8',15'-apocarotene-dial. These data demonstrate for the first time that the orthologue of lignostilbene-α,β-dioxygenase found in the carotenogenic phototrophic bacterium has the 15,15' double bond cleavage activity towards both the acyclic carotenoids and cyclic apocarotenoid.
类胡萝卜素裂解双加氧酶通过在类胡萝卜素特定双键处进行氧化裂解，催化类胡萝卜素衍生物以及植物激素脱落酸和独脚金内酯前体的形成。在沼泽红假单胞菌的基因组中发现了一个编码假定细菌双加氧酶的基因，该酶与木质芪-α,β-双加氧酶同源。通过分析重组大肠杆菌菌株中的类胡萝卜素衍生物，发现该假定双加氧酶催化番茄红素和神经孢烯的15,15'双键裂解。含有重组蛋白的细胞裂解物将全反式-β-apo-8'-胡萝卜醛在15,15'双键处裂解为视黄醛和apo-8',15'-类胡萝卜素二醛。这些数据首次证明，在产类胡萝卜素的光合细菌中发现的木质芪-α,β-双加氧酶的直向同源物对无环类胡萝卜素和环状类胡萝卜素衍生物均具有15,15'双键裂解活性。
