Endo T, Oya M, Joubert F J, Hayashi K, Miyazawa T
Department of Chemistry, College of Technology, Gunma University, Kiryu, Japan.
J Protein Chem. 1989 Aug;8(4):583-8. doi: 10.1007/BF01026441.
Proton nuclear magnetic resonance (NMR) spectra have been recorded of various neurotoxins from snake venoms. pH dependence of the chemical shifts and resonance intensity has been followed for the functionally essential Trp-29. The indole N-1 proton of Trp-29 in alpha-bungarotoxin, toxin B, and cobrotoxin exhibits appreciably large upfield shifts as the pH is lowered and the suppressed exchange with the solvent hydrogen at pH 3-4, but not in Naja haje annulifera 10 where Asp-31 is replaced with Gly-31. This observation strongly suggests the presence of a hydrogen bond between Trp-29 and Asp-31 that is probably important in stabilizing the arrangement of the functionally essential residues to form a distinct binding region for the receptor.
已记录了来自蛇毒的各种神经毒素的质子核磁共振（NMR）光谱。对功能必需的色氨酸-29，跟踪了化学位移和共振强度的pH依赖性。在α-银环蛇毒素、毒素B和眼镜蛇毒素中，色氨酸-29的吲哚N-1质子随着pH降低呈现明显的大的高场位移，并且在pH 3-4时与溶剂氢的交换受到抑制，但在Asp-31被Gly-31取代的埃及眼镜蛇10中则没有这种情况。这一观察结果强烈表明色氨酸-29和天冬氨酸-31之间存在氢键，这可能对稳定功能必需残基的排列以形成与受体的独特结合区域很重要。
