Lugovskoy A A, Maslennikov I V, Utkin Y N, Tsetlin V I, Cohen J B, Arseniev A S
Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow.
Eur J Biochem. 1998 Jul 15;255(2):455-61. doi: 10.1046/j.1432-1327.1998.2550455.x.
The three-dimensional structure of a synthetic peptide corresponding to the putative transmembrane segment M3 (amino acid residues 277-301) of the alpha subunit of the nicotinic acetylcholine receptor from Torpedo californica has been studied by means of two-dimensional 1H-NMR spectroscopy in a chloroform/methanol (1:1) mixture containing 0.1 M LiClO4. Complete resonance assignment has been performed using double-quantum-filtered COSY (DQF-COSY), TOCSY and NOESY spectra. The spatial structure has been calculated using the Diana program on the basis of integrated intensities of NOESY spectra. HN-C(alpha)H and HC(alpha)-C(beta)H spin-spin coupling constants. Residues 279-297 of M3 form a right-handed helix (root mean square deviation is 0.032 nm for backbone atoms and 0.088 nm for all heavy atoms). The conformations of the 17 side chains have been unambiguously determined. The obtained structure is in accord with the photolabeling pattern of the membrane nicotinic acetylcholine receptor (nAChR) which suggests alpha-helical structure of M3 in the labeled portion [Blanton, M. P. & Cohen, J. B. (1994) Biochemistry 33, 2859-2872].
利用二维¹H-NMR光谱，在含有0.1 M高氯酸锂的氯仿/甲醇（1:1）混合物中，研究了来自加州电鳐的烟碱型乙酰胆碱受体α亚基假定跨膜片段M3（氨基酸残基277 - 301）的合成肽的三维结构。使用双量子滤波COSY（DQF-COSY）、TOCSY和NOESY光谱完成了全共振归属。基于NOESY光谱的积分强度，使用Diana程序计算了空间结构。HN-C(α)H和HC(α)-C(β)H自旋-自旋耦合常数。M3的279 - 297位残基形成一个右手螺旋（主链原子的均方根偏差为0.032 nm，所有重原子的均方根偏差为0.088 nm）。明确确定了17条侧链的构象。所得结构与膜烟碱型乙酰胆碱受体（nAChR）的光标记模式一致，该模式表明标记部分的M3具有α螺旋结构[布兰顿，M. P. & 科恩，J. B.（1994年）《生物化学》33卷，2859 - 2872页]。
