Lai Denton, Springstead James R, Monbouquette Harold G
Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, 5531 Boelter Hall, 420 Westwood Plaza, Los Angeles, CA 90095, USA.
Extremophiles. 2008 Mar;12(2):271-8. doi: 10.1007/s00792-007-0126-6. Epub 2007 Dec 22.
The archaea are distinguished by their unique isoprenoid ether lipids, which typically consist of the sn-2,3-diphytanylglycerol diether or sn-2,3-dibiphytanyldiglycerol tetraether core modified with a variety of polar headgroups. However, many hyperthermophilic archaea also synthesize tetraether lipids with up to four pentacyclic rings per 40-carbon chain, presumably to improve membrane thermal stability at temperatures up to approximately 110 degrees C. This study aimed to correlate the ratio of tetraether to diether core lipid, as well as the presence of pentacyclic groups in tetraether lipids, with growth temperature for the hyperthermophilic archaeon, Archaeoglobus fulgidus. Analysis of the membrane core lipids of A. fulgidus using APCI-MS analysis revealed that the tetraether-to-diether lipid ratio increases from 0.3 +/- 0.1 for cultures grown at 70 degrees C to 0.9 +/- 0.1 for cultures grown at 89 degrees C. Thin-layer chromatography (TLC) followed by APCI-MS analysis provided evidence for no more than one pentacycle in the hydrocarbon chains of tetraether lipid from cultures grown at 70 degrees C and up to 2 pentacycles in the tetraether lipid from cultures grown at higher temperatures. Analysis of the polar lipid extract using TLC and negative-ion ESI-MS suggested the presence of diether and tetraether phospholipids with inositol, glycosyl, and ethanolamine headgroup chemistry.
古菌以其独特的类异戊二烯醚脂为特征，这些脂通常由sn-2,3-二植烷甘油二醚或sn-2,3-二双植烷二甘油四醚核心组成，并带有多种极性头部基团。然而，许多嗜热古菌还合成每40碳链含有多达四个五环的四醚脂，推测这是为了在高达约110摄氏度的温度下提高膜的热稳定性。本研究旨在将嗜热古菌嗜热栖热袍菌的四醚与二醚核心脂的比例以及四醚脂中五环基团的存在与生长温度关联起来。使用大气压化学电离质谱（APCI-MS）分析嗜热栖热袍菌的膜核心脂，结果显示，对于在70摄氏度下培养的菌株，四醚与二醚脂的比例从0.3±0.1增加到在89摄氏度下培养的菌株的0.9±0.1。薄层色谱（TLC）随后进行APCI-MS分析表明，在70摄氏度下培养的菌株的四醚脂烃链中五环不超过一个，而在较高温度下培养的菌株的四醚脂中五环最多有两个。使用TLC和负离子电喷雾电离质谱（ESI-MS）分析极性脂提取物表明存在带有肌醇、糖基和乙醇胺头部基团化学结构的二醚和四醚磷脂。
