Pinheiro T J, Vaz W L, Geraldes C F, Prado A, da Costa M S
Departamento de Química, Universidade de Coimbra, Portugal.
Biochem Biophys Res Commun. 1987 Oct 14;148(1):397-402. doi: 10.1016/0006-291x(87)91124-7.
The membrane lipids of a thermophilic bacterium, Thermus SPS11, isolated from thermal springs in São Pedro do Sul, Portugal, were fractionated by chromatography on silica gel. The total lipid extract was found to contain one major phospholipid (PL), which accounts for about 90% of the total lipid phosphorous, and one major glycolipid (GL), which accounts for about 95% of the total carbohydrate in the non-phospholipid fraction. The membranes also contain about 11% by weight of a complex mixture of carotenoids (CA). Multilamellar liposomes, in excess water, formed from PL and mixtures of PL with GL and CA in proportions found in the natural membrane were investigated by proton-decoupled 31P-nuclear magnetic resonance (NMR) spectroscopy and X-ray diffraction. All mixtures examined were found to be in a lamellar phase with disordered hydrophobic chains with no evidence for "non-bilayer structures" between 23 degrees and 85 degrees C. Compared to bilayers formed from pure PL or mixtures of PL and CA, significantly larger values for the chemical shift anisotropy of the 31P-NMR powder patterns were obtained from bilayers formed from mixtures of PL and GL, at temperatures above 75 degrees C, and mixtures of PL, GL and CA at all temperatures examined. These differences are interpreted in terms of changes in the order of the bilayer and/or changes in the orientation of the phosphate moiety of PL. The significance of these results to the thermophily of the bacterium is discussed.
从葡萄牙南圣佩德罗温泉中分离出的嗜热细菌Thermus SPS11的膜脂，通过硅胶柱色谱法进行分离。发现总脂质提取物中含有一种主要磷脂（PL），约占总脂质磷的90%，以及一种主要糖脂（GL），约占非磷脂部分总碳水化合物的95%。该膜还含有约11%（重量）的类胡萝卜素（CA）复杂混合物。利用质子去耦31P核磁共振（NMR）光谱和X射线衍射研究了由PL以及按天然膜中发现的比例混合的PL与GL和CA在过量水中形成的多层脂质体。在所研究的所有温度范围内（23℃至85℃），发现所有检测的混合物均处于具有无序疏水链的层状相，没有“非双层结构”的证据。与由纯PL或PL与CA的混合物形成的双层相比，在75℃以上温度下，由PL与GL的混合物形成的双层以及在所有检测温度下由PL、GL和CA的混合物形成的双层，其31P-NMR粉末图谱的化学位移各向异性值显著更大。这些差异可以从双层排列顺序的变化和/或PL磷酸基团取向的变化来解释。讨论了这些结果对该细菌嗜热性的意义。
