Rees B, Samama J P, Thierry J C, Gilibert M, Fischer J, Schweitz H, Lazdunski M, Moras D
Proc Natl Acad Sci U S A. 1987 May;84(10):3132-6. doi: 10.1073/pnas.84.10.3132.
Cardiotoxin VII4 from Naja mossambica mossambica crystallizes in space group P61 (a = b = 73.9 A; c = 59.0 A) with two molecules of toxin (molecular mass = 6715 Da) in the asymmetric unit. The structure was solved by using a combination of multiple isomorphous replacement and density modification methods. Model building and least-squares refinement led to an agreement factor of 27% for a data set to 3-A resolution prior to any inclusion of solvent molecules. The topology of the molecule is similar to that found in short and long snake neurotoxins, which block the nicotinic acetylcholine receptor. Major differences occur in the conformation of the central loop, resulting in a change in the concavity of the molecule. Hydrophobic residues are clustered in two distinct areas. The existence of stable dimeric entities in the crystalline state, with the formation of a six-stranded antiparallel beta sheet, may be functionally relevant.
来自莫桑比克眼镜蛇的心脏毒素VII4在空间群P61（a = b = 73.9 Å；c = 59.0 Å）中结晶，不对称单元中有两个毒素分子（分子量 = 6715 Da）。该结构通过多重同晶置换和密度修正方法相结合得以解析。在未包含任何溶剂分子之前，模型构建和最小二乘法精修使得3 Å分辨率数据集的拟合因子达到27%。该分子的拓扑结构与在短和长蛇神经毒素中发现的拓扑结构相似，这些神经毒素会阻断烟碱型乙酰胆碱受体。主要差异出现在中央环的构象上，导致分子凹度发生变化。疏水残基聚集在两个不同区域。晶体状态下稳定二聚体实体的存在以及六链反平行β折叠的形成可能具有功能相关性。
