Blanc E, Romi-Lebrun R, Bornet O, Nakajima T, Darbon H
AFMB, CNRS UPR 9039, IFR1, 31, Marseille, France.
Biochemistry. 1998 Sep 8;37(36):12412-8. doi: 10.1021/bi9809371.
The solution structure of BmTX2 purified from the venom of the Chinese Buthid Buthus martensi has been determined by 2D NMR spectroscopy techniques which led to the description of its 3D conformation. The structure consists of a triple-stranded beta-sheet connected to a helical structure. This helix encompasses 10 residues, from 11 to 20, begins with a turn of 310 helix, and ends with an alpha helix. The three strands of beta sheet comprise residues 2-6, with a bulge covering residues 4 and 5, 26-29, and 32-35, with a type I' beta turn centered on residues 30-31. We also characterized the solution structure of BmTX1. The two toxins which are potent blockers of both large-conductance calcium-activated potassium channels (BKCa channels) and voltage-gated potassium channels (Kv1. 3) are highly superimposable and possess the same structural characteristics. Analysis of these structures allows us to hypothesize that, besides the main surface of interaction described by the functional map of charybdotoxin, one can expect that the binding of scorpion toxins on BKCa channels may involve residues on the edge of this surface.
已通过二维核磁共振光谱技术确定了从中国钳蝎（东亚钳蝎）毒液中纯化得到的BmTX2的溶液结构，该技术使人们得以描述其三维构象。该结构由连接到螺旋结构的三链β-折叠组成。该螺旋包含10个残基，从11到20，起始于一个310螺旋的转角，终止于一个α螺旋。β-折叠的三条链包括残基2 - 6，其中有一个覆盖残基4和5的凸起，26 - 29，以及32 - 35，在残基30 - 31处有一个I'型β-转角。我们还对BmTX1的溶液结构进行了表征。这两种毒素都是大电导钙激活钾通道（BKCa通道）和电压门控钾通道（Kv1.3）的有效阻滞剂，它们高度重叠且具有相同的结构特征。对这些结构的分析使我们能够推测，除了由沙蚕毒素功能图谱描述的主要相互作用表面外，可以预期蝎毒素与BKCa通道的结合可能涉及该表面边缘的残基。
