Important roles for membrane lipids in haloarchaeal bioenergetics
Important roles for membrane lipids in haloarchaeal bioenergetics
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DOI：
10.1016/j.bbamem.2016.08.010
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发表时间：
2016-11-01
影响因子：
3.4
通讯作者：
Valentine, David L.
中科院分区：
文献类型：
--
作者：
Kellermann, Matthias Y.;Yoshinaga, Marcos Y.;Valentine, David L.
脂肪组学分析结合各种生理实验的最新进展为破译嗜盐古菌膜脂类的结构与功能奠定了基础。在这里，我们主要关注了Haloferax Volcanii的脂肪组成的变化，但也与其他四个代表不同细胞形态和行为(即杆状和多形性行为)的盐生盐生杆菌、Halorubrum lacusDeep di、Halorubrum soomense和HaloPlanus Natans进行了比较分析。我们的数据显示，所有五种海洋生物都含有非常高水平的菜籽酮，高达总脂肪的72%。这种普遍存在的现象表明，菜籽酮的功能可能超出了它们作为电子和质子转运体的普通作用，同时作为离子通透性屏障和对抗氧化应激的强大屏障。此外，我们的目的是了解阳离子与嗜盐古菌膜的特征负电荷表面相互作用的作用。例如，我们提出，通过桥接相邻阴离子磷脂的负电荷，镁离子可以作为心磷脂的替代品，心磷脂是一种已知的控制膜曲率应力的分子。这项研究进一步提供了一种生物能量学的观点，即在地球大气层氧化后，盐生古生菌是如何进化的。海洋生物有氧生活方式的成功包括多种基于膜的策略，这些策略成功地平衡了对坚固的双层结构的需求和对高电子传输速率的需求--共同代表了居住在地球周围高盐度水体的分子基础。爱思唯尔出版公司(Elsevier B.V.)
Recent advances in lipidomic analysis in combination with various physiological experiments set the stage for deciphering the structure-function of haloarchaeal membrane lipids. Here we focused primarily on changes in lipid composition of Haloferax volcanii, but also performed a comparative analysis with four other haloarchaeal species (Halobacterium salinarum, Halorubrum lacusprofundi, Halorubrum sodomense and Haloplanus natans) all representing distinctive cell morphologies and behaviors (i.e., rod shape vs. pleomorphic behavior). Common to all five haloarchaea, our data reveal an extraordinary high level of menaquinone, reaching up to 72% of the total lipids. This ubiquity suggests that menaquinones may function beyond their ordinary role as electron and proton transporter, acting simultaneously as ion permeability barriers and as powerful shield against oxidative stress. In addition, we aimed at understanding the role of cations interacting with the characteristic negatively charged surface of haloarchaeal membranes. We propose for instance that by bridging the negative charges of adjacent anionic phospholipids, Mg2+ acts as surrogate for cardiolipin, a molecule that is known to control curvature stress of membranes. This study further provides a bioenergetic perspective as to how haloarchaea evolved following oxygenation of Earth's atmosphere. The success of the aerobic lifestyle of haloarchaea includes multiple membrane-based strategies that successfully balance the need for a robust bilayer structure with the need for high rates of electron transport - collectively representing the molecular basis to inhabit hypersaline water bodies around the planet. Published by Elsevier B.V.