Scolnik P A, Walker M A, Marrs B L
J Biol Chem. 1980 Mar 25;255(6):2427-32.
We have characterized the carotenoids accumulated by a series of mutants of Rhodopseudomonas capsulata as part of a study of the synthesis, structure, and function of the photosynthetic membranes of this bacterium. The carotenoids in this study were identified by visible and mass spectroscopy, chromatography, derivatization, and chemical analyses. We have located a new genetic region, crtF, necessary for the O-methylation of the carotenoids. Mutants with a lesion in crtF accumulate demethylspheroidene as their major carotenoid during anaerobic growth and demethylspheroidenone when grown in the presence of oxygen, a heretofore undescribed phenotype. The genetic region necessary for O-methylation maps adjacent to the known cluster of genes affecting carotenoid biosynthesis. In addition, we have identified methoxyneurosporene as the carotenoid that preferentially binds to the reaction centers of strain Ga, a green mutant of R. sphaeroides which accumulates three neurosporene-like carotenoids. A metabolic grid for carotenoid biosynthesis is proposed, based upon the intermediates accumulated in these mutants.
作为对这种细菌光合膜的合成、结构和功能研究的一部分，我们已对荚膜红假单胞菌一系列突变体积累的类胡萝卜素进行了表征。本研究中的类胡萝卜素通过可见光谱和质谱、色谱法、衍生化和化学分析进行鉴定。我们发现了一个新的基因区域crtF，它是类胡萝卜素O-甲基化所必需的。在crtF中有损伤的突变体在厌氧生长期间积累去甲基球形烯作为其主要类胡萝卜素，而在有氧条件下生长时积累去甲基球形烯酮，这是一种迄今未描述的表型。O-甲基化所需的基因区域定位于与影响类胡萝卜素生物合成的已知基因簇相邻的位置。此外，我们已鉴定出甲氧基神经孢烯是优先结合菌株Ga反应中心的类胡萝卜素，Ga是球形红细菌的一个绿色突变体，它积累三种神经孢烯样类胡萝卜素。基于这些突变体中积累的中间体，提出了类胡萝卜素生物合成的代谢网络。
