Oppenheimer N J, Bodley J W
J Biol Chem. 1981 Aug 25;256(16):8579-81.
Diphtheria toxin inactivates protein synthesis elongation factor 2 by catalyzing the ADP-ribosylation of a novel derivative of histidine, diphthamide, in the protein (Van Ness, B. G., Howard, J. B., and Bodley, J. W. (1980) J. Biol. Chem. 255, 10710-10716). In this report, we describe experiments involving nuclear Overhauser enhancement NMR spectroscopy which were undertaken to elucidate the site of ADP-ribosylation of diphthamide and the configuration of the glycosidic bond formed by the toxin. The essential result of these experiments is that, in ribosyl-diphthamide obtained by enzymatic digestion of ADP-ribosyl-elongation factor-2, the H-5 imidazole proton is near the R-4 proton of ribose. This result and others are consistent with the interpretation that diphtheria toxin covalently attaches ADP-ribose to the imidazole N-1 of diphthamide via an alpha-glycosidic linkage.
白喉毒素通过催化蛋白质中一种新型组氨酸衍生物——双氢酰胺的ADP核糖基化作用，使蛋白质合成延伸因子2失活（范内斯，B.G.，霍华德，J.B.，和博德利，J.W.（1980年）《生物化学杂志》255卷，第10710 - 10716页）。在本报告中，我们描述了利用核Overhauser增强核磁共振光谱进行的实验，这些实验旨在阐明双氢酰胺的ADP核糖基化位点以及毒素形成的糖苷键构型。这些实验的关键结果是，在通过酶促消化ADP核糖基延伸因子2得到的核糖基双氢酰胺中，咪唑H - 5质子靠近核糖的R - 4质子。这一结果及其他结果与白喉毒素通过α - 糖苷键将ADP核糖共价连接到双氢酰胺的咪唑N - 1上的解释相一致。
