Jackson S K, James P E, Rowlands C C, Mile B
Department of Medical Microbiology, University of Wales College of Medicine, Cardiff, UK.
Biochim Biophys Acta. 1992 Jun 10;1135(2):165-70. doi: 10.1016/0167-4889(92)90133-v.
The molecular mechanisms of endotoxin action are poorly understood. A prerequisite to cellular activation by this agent must be interaction (binding) with the plasma membrane. In this study we have investigated the role of the polysaccharide region of endotoxin (LPS) in binding to macrophages and macrophage-like cell lines. The LPS molecules, from Escherichia coli O111.B4, J5 and the lipid-A, were spin labelled with 2,2,6,6-tetramethylpiperidine-N-oxyl] (Tempo) free radical in their sugar residues, and examined by electron spin resonance spectroscopy. This is the first report of the synthesis of spin-labelled endotoxins. Measurement of the rotational correlation times (Tc) indicated that the saccharide resides do not bind to membrane surface structures and suggests that the binding of LPS to macrophages is mediated by the lipid acyl chains. Anti-sera to LPS from E. coli O111.B4 was effective in binding to the polysaccharide of the same LPS bound to the cell surface.
内毒素作用的分子机制目前还知之甚少。该物质激活细胞的一个先决条件必须是与质膜相互作用（结合）。在本研究中，我们研究了内毒素（LPS）的多糖区域在与巨噬细胞和巨噬细胞样细胞系结合中的作用。来自大肠杆菌O111.B4、J5的LPS分子以及脂质A在其糖残基上用2,2,6,6 - 四甲基哌啶 - N - 氧基]（Tempo）自由基进行自旋标记，并通过电子自旋共振光谱进行检测。这是关于自旋标记内毒素合成的首次报道。旋转相关时间（Tc）的测量表明，糖残基不与膜表面结构结合，这表明LPS与巨噬细胞的结合是由脂质酰基链介导的。针对大肠杆菌O111.B4 LPS的抗血清能够有效地结合到与细胞表面结合的相同LPS的多糖上。
