Favreau P, Krimm I, Le Gall F, Bobenrieth M J, Lamthanh H, Bouet F, Servent D, Molgo J, Ménez A, Letourneux Y, Lancelin J M
Laboratoire de Synthèses et Etudes de Substances Naturelles à Activités Biologiques, Université de La Rochelle, Pôle Sciences, Av. Marillac, 17042 La Rochelle Cedex, France.
Biochemistry. 1999 May 11;38(19):6317-26. doi: 10.1021/bi982817z.
Two novel alpha-conotoxins were purified and characterized from the venom of the fish-hunting cone snail Conus consors. These peptides were identified by screening HPLC fractions of the crude venom and by binding experiments with Torpedo nicotinic acetylcholine receptor. The toxins named alpha-CnIA and alpha-CnIB exhibited sequences of 14 and 12 amino acids, respectively. The alpha-CnIA represents the main alpha-conotoxin contained in the venom, whereas alpha-CnIB is present in a relatively small amount. Chemical synthesis of alpha-CnIA was carried out using the Fmoc methodology by selective disulfide bond formation. The biological activity of the toxin was assessed in fish and mice. The alpha-CnIA inhibited the fixation of iodinated alpha-bungarotoxin to Torpedo nicotinic acetylcholine receptors with an IC50 of 0.19 microM which can be compared to the IC50 of 0.31 microM found for the previously characterized alpha-MI isolated from the piscivorous Conus magus. The synthetic alpha-CnIA blocked spontaneous and evoked synaptic potentials in frog and mouse isolated neuromuscular preparations at sub-micromolar concentrations. Solution NMR of this toxin indicated a conformational heterogeneity with the existence of different conformers in solution, at slow and intermediate exchange rates relative to the NMR chemical shift time scale, similar to that reported for alpha-GI and alpha-MI. NMR structures were calculated for the major NMR signals representing more than 80% of the population at 5 degrees C.
从食鱼芋螺Conus consors的毒液中纯化并鉴定出两种新型α-芋螺毒素。通过筛选粗毒液的高效液相色谱馏分以及与电鳐烟碱型乙酰胆碱受体进行结合实验来鉴定这些肽。命名为α-CnIA和α-CnIB的毒素分别具有14个和12个氨基酸的序列。α-CnIA是毒液中主要的α-芋螺毒素，而α-CnIB含量相对较少。使用Fmoc方法通过选择性二硫键形成对α-CnIA进行化学合成。在鱼类和小鼠中评估了该毒素的生物活性。α-CnIA抑制碘化α-银环蛇毒素与电鳐烟碱型乙酰胆碱受体的结合，IC50为0.19微摩尔，可与从食鱼芋螺Conus magus中分离出的先前鉴定的α-MI的0.31微摩尔IC50相比较。合成的α-CnIA在亚微摩尔浓度下可阻断青蛙和小鼠离体神经肌肉制剂中的自发和诱发突触电位。该毒素的溶液核磁共振表明存在构象异质性，在溶液中存在不同的构象体，相对于核磁共振化学位移时间尺度，其交换速率较慢和中等，类似于报道的α-GI和α-MI。在5℃下计算了代表超过80%群体的主要核磁共振信号的核磁共振结构。
