A polycyclic terpenoid that alleviates oxidative stress
A polycyclic terpenoid that alleviates oxidative stress
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DOI：
10.1073/pnas.0800199105
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发表时间：
2008-05-06
影响因子：
11.1
通讯作者：
Pearson, A.
中科院分区：
文献类型：
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作者：
Bosak, T.;Losick, R. M.;Pearson, A.
多环萜类类脂，如藿烷和甾烷，已被广泛用于了解古代生物、地球历史和海洋-大气系统的氧合作用。其中一些脂质被认为只由有氧生物产生，而另一些实际上需要分子氧来进行生物合成。一个长期存在的问题是：某些多环脂最初是在某些环境或代谢压力(包括氧气的存在)下进化的吗？在这里，我们鉴定了枯草杆菌芽胞中的四环异戊二烯类化合物。我们称它们为孢子烯。它们是通过常规聚戊烯的环化反应产生的，这种反应在化学上比从角鲨烯生成萜类化合物(如石油烯和类固醇)更有利。反应的简单性表明枯草杆菌环化酶可能类似于进化上古老的环化酶。我们发现，这些分子增加了孢子对活性氧的抵抗力，证明了非色素细菌脂类生物标记物的特殊生理作用。因此，沉积物中这些化合物的地质稳定性衍生物可以作为氧化应激和有氧环境的直接指示器。
Polycyclic terpenoid lipids such as hopanes and steranes have been widely used to understand ancient biology, Earth history, and the oxygenation of the ocean-atmosphere system. Some of these lipids are believed to be produced only by aerobic organisms, whereas others actually require molecular oxygen for their biosynthesis. A persistent question remains: Did some polycyclic lipids initially evolve in response to certain environmental or metabolic stresses, including the presence of oxygen? Here, we identify tetracyclic isoprenoids in spores of the bacterium Bacillus subtilis. We call them sporulenes. They are produced by cyclization of regular polyprenes, a reaction that is more favorable chemically than the formation of terpenoids such as hopanoids and steroids from squalene. The simplicity of the reaction suggests that the B. subtilis cyclase may be analogous to evolutionarily ancient cyclases. We show that these molecules increase the resistance of spores to a reactive oxygen species, demonstrating a specific physiological role for a nonpigment bacterial lipid biomarker. Geostable derivatives of these compounds in sediments could thus be used as direct indicators of oxidative stress and aerobic environments.