Wynants C, Van Binst G, Loosli H R
Int J Pept Protein Res. 1985 Jun;25(6):615-21.
The possible conformations of SMS 201-995, an active analogue of somastostatin, have been studied in dimethylsulfoxide solution by 500 MHz proton n.m.r. spectroscopy. The assignments have been made by use of 2D-correlated methods to detect long-range coupling connectivities in aromatic residues and between the alpha protons of consecutive residues. NOESY experiments enabled us to correlate amide and alpha protons of neighbouring amino acid residues, which indicate a less flexible situation than in water. Measurements of temperature coefficients of the amide protons, of NH-C alpha H coupling constants and NOE effects are in favour of one predominant conformation with a beta turn, of type II', involving amino acids Phe3 to Thr6.
生长抑素的活性类似物SMS 201 - 995在二甲基亚砜溶液中的可能构象已通过500兆赫质子核磁共振光谱进行了研究。通过二维相关方法进行归属，以检测芳香族残基中以及连续残基的α质子之间的远程耦合连接性。核Overhauser效应光谱实验使我们能够关联相邻氨基酸残基的酰胺质子和α质子，这表明其构象灵活性低于在水中的情况。酰胺质子的温度系数、NH - CαH耦合常数和核Overhauser效应的测量结果支持一种具有II'型β转角的主要构象，该构象涉及苯丙氨酸3至苏氨酸6。
