STRUCTURE OF ESCHERICHIA-COLI MEMBRANES - GLYCEROL AUXOTROPHS AS A TOOL FOR THE ANALYSIS OF THE PHOSPHOLIPID HEADGROUP REGION BY DEUTERIUM MAGNETIC-RESONANCE
STRUCTURE OF ESCHERICHIA-COLI MEMBRANES - GLYCEROL AUXOTROPHS AS A TOOL FOR THE ANALYSIS OF THE PHOSPHOLIPID HEADGROUP REGION BY DEUTERIUM MAGNETIC-RESONANCE
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DOI：
10.1021/bi00510a017
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发表时间：
1981-01-01
期刊：
影响因子：
2.9
通讯作者：
SEELIG, J
中科院分区：
文献类型：
--
作者：
GALLY, HU;PLUSCHKE, G;SEELIG, J
合成了在不同位置选择性氘代的甘油，并将其供应到E. coli菌株T131 GP，该菌株在内源甘油合成和甘油降解方面有缺陷，并且缺乏合成心磷脂的能力。该方法能够立体特异性标记膜磷脂（约80%磷脂酰乙醇胺，约20%磷脂酰甘油）。氘磁共振[2 H-NMR]光谱获得细胞膜和脂质分散体无论是从总脂质提取物或从纯化的磷脂酰甘油或磷脂酰乙醇胺。当使用在不同位置氘代的甘油时，可以分配磷脂酰甘油中的磷脂甘油主链和末端甘油部分的所有共振。甘油骨架的分子构象与研究的磷脂种类无关，也不会因存在大量膜蛋白而改变。对于2 H-NMR分裂的定量解释，提出了一种模型，该模型假设围绕甘油c（2）sbdC（3）键的基本自由旋转与围绕C（1）sbdC（2）键的不对称和受限跳跃过程相结合。该模型与磷脂分子的已知X射线结构兼容。甘油骨架C（1）和C（3）片段的2个氘核是磁性不等价的。立体选择性单氘化消除了一组四极分裂在这两种情况下。
Glycerol selectively deuterated at various positions was synthesized and supplied to the growth medium of E. coli strain T131 GP, which is defective in endogenous glycerol synthesis and glycerol degradation and lacks the ability to synthesize cardiolipin. The procedure enables the stereospecific labeling of the membrane phospholipids (.apprx. 80% phosphatidylethanolamine, .apprx. 20% phosphatidylglycerol). Deuterium magnetic resonance [2H-NMR] spectra were obtained for cell membranes and lipid dispersions either from total lipid extracts or from purified phosphatidylglycerol or phosphatidylethanolamine. When glycerol deuterated at various positions was used, all resonances of the phospholipid glycerol backbone and the terminal glycerol moiety in phosphatidylglycerol could be assigned. The molecular conformation of the glycerol backbone is independent of the phospholipid species investigated and also is not altered by the presence of high amounts of membrane proteins. For the quantitative interpretation of the 2H-NMR splittings, a model is proposed which assumes essentially free rotation around the glycerol c(2).sbd.C(3) bond combined with an asymmetric and restricted jump process around the C(1).sbd.C(2) bond. This model is compatible with known X-ray structures of phospholipid molecules. The 2 deuterons of both the glycerol backbone C(1) and C(3) segments were magnetically inequivalent. Stereoselective monodeuteration eliminated one set of quadrupole splittings in both cases.