Martins J C, Zhang W G, Tartar A, Lazdunski M, Borremans F A
Laboratory of Organic Chemistry, State University Ghent, Belgium.
FEBS Lett. 1990 Jan 29;260(2):249-53. doi: 10.1016/0014-5793(90)80115-y.
A proton NMR study at 500 MHz of leiurotoxin I in water is presented. Nearly complete sequence-specific assignments of the individual backbone and side-chain proton resonances were achieved using through-bond and through-space connectivities obtained from standard two-dimensional NMR techniques. The secondary structure of this toxin is inferred from a combination of short-range nuclear Overhauser enhancements, scalar couplings and proton/deuteron exchange rates. Three disulfide bridges locate the N-terminal part (that is alpha-helical from residue 6 to 16) on one side of a C-terminal two stranded antiparallel beta sheet (from Leu18 to Val29). The latter features a tight turn at Gly23-Asp24.
本文展示了在500兆赫下对水中的类毒素I进行的质子核磁共振研究。利用从标准二维核磁共振技术获得的键连和空间连接性，几乎实现了对各个主链和侧链质子共振的完整序列特异性归属。该毒素的二级结构是通过短程核Overhauser效应、标量耦合和质子/氘核交换率的综合分析推断出来的。三个二硫键将N端部分（即从第6位到第16位残基为α螺旋）定位在C端两链反平行β折叠（从Leu18到Val29）的一侧。后者在Gly23 - Asp24处有一个紧密转角。
