Even though organisms with squalene hopene cyclase activity involved in hopanoid synthesis has been reported earlier, their existence along with carotenoid synthesis is rarely reported. Here, we report the existence of hopanoid and C30 carotenoid biosynthetic pathway in Pseudomonas mendocina, the squalene hopene cyclase producing endophyte of the medicinal plant Murraya koenigii. The enzyme squalene hopene cyclase from Pseudomonas mendocina is involved in the synthesis of dehydrosqualene-mediated alternate pathway for carotenoid biosynthesis. The hopanoids are involved in membrane stability and integrity, and the carotene chromophores are involved in the photo protection of the cell. The orange-colored C30 carotenoid pigment 4-4' diaponeurosporenic acid in the extracellular extract of Pseudomonas mendocina with squalene cyclase activity was detected by the combination of UV/Vis spectrometry, FTIR, and Mass Spectrometry. 4-4' diaponeurosporenic acid could be traced as the end product of the carotenoid pathway and belonged to the xanthophyll group of carotenoids.

中文翻译：

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4–4' diaponeurosporenic Acid，内生性门多西那假单胞菌中的 C30 类胡萝卜素色素，具有角鲨烯环化酶活性

尽管较早报道了具有参与hopanoid合成的角鲨烯希望烯环化酶活性的生物体，但很少报道它们与类胡萝卜素合成一起存在。在这里，我们报告了在 Pseudomonas mendocina 中存在hopanoid 和 C30 类胡萝卜素生物合成途径，Pseudomonas mendocina 是药用植物 Murraya koenigii 的产生角鲨烯环化酶的内生菌。来自门多克假单胞菌的角鲨烯环化酶参与脱氢角鲨烯介导的类胡萝卜素生物合成替代途径的合成。hopanoids 参与膜的稳定性和完整性，胡萝卜素发色团参与细胞的光保护。橙色 C30 类胡萝卜素色素 4-4' 通过紫外/可见光谱、FTIR 和质谱的组合检测了具有角鲨烯环化酶活性的门多克假单胞菌胞外提取物中的 diaponeurosporenic 酸。4-4' diaponeurosporenic acid 可以被追踪为类胡萝卜素途径的终产物，属于类胡萝卜素的叶黄素组。