Functional convergence of hopanoids and sterols in membrane ordering
Functional convergence of hopanoids and sterols in membrane ordering
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DOI：
10.1073/pnas.1212141109
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发表时间：
2012-08-28
影响因子：
11.1
通讯作者：
Simons, Kai
中科院分区：
文献类型：
--
作者：
Saenz, James Peter;Sezgin, Erdinc;Simons, Kai
液体有序相是两种具有生物化学活性的膜状态之一，到目前为止一直被认为是真核膜脂类相互作用的独特结果。液体有序相的形成主要取决于甾醇的有序性。然而，目前尚不清楚这种能力是否存在于缺乏类固醇的生物体中，如细菌。我们证明了新喋醇，一种最简单的细菌类胡萝卜素，具有类似的性质，并且类胡萝卜素是细菌的“甾醇替代品”，能够排列饱和脂肪并在模型膜中形成液体有序相。这些观察表明，有序的生物化学活性液膜的进化可能在地球表面的氧化和类固醇出现之前就已经进化了。
Liquid-ordered phases are one of two biochemically active membrane states, which until now were thought to be a unique consequence of the interactions between eukaryotic membrane lipids. The formation of a liquid-ordered phase depends crucially on the ordering properties of sterols. However, it is not known whether this capacity exists in organisms that lack sterols, such as bacteria. We show that diplopterol, the simplest bacterial hopanoid, has similar properties and that hopanoids are bacterial "sterol surrogates" with the ability to order saturated lipids and to form a liquid-ordered phase in model membranes. These observations suggest that the evolution of an ordered biochemically active liquid membrane could have evolved before the oxygenation of Earth's surface and the emergence of sterols.