Reddy G L, Nagaraj R
Int J Pept Protein Res. 1987 Apr;29(4):497-503. doi: 10.1111/j.1399-3011.1987.tb02276.x.
The conformations of synthetic peptides which span the region in which the precursor part of proteins (signal sequences) destined for export are cleaved by signal peptidases, were investigated by circular dichroism spectroscopy. Pentapeptides comprising amino acids only from the carboxy-terminus of signal sequences or the amino terminus of the mature protein do not have any preferred conformation in a variety of solvents. Octa- and nonapeptides containing amino acids from the carboxy-terminal protion of signal sequences and the amino-terminus of the mature portions of precursor proteins tend to adopt beta-turn conformations in trifluoroethanol and micelles of sodium dodecylsulphate. Hence, in addition to the distribution of amino acids with small side chains at the carboxy terminus of signal sequences, it is conceivable that signal peptidases also recognize a beta-turn conformation in the cleavage site region of precursor proteins.
通过圆二色光谱法研究了跨越蛋白质前体部分（信号序列）中注定要输出的部分被信号肽酶切割的区域的合成肽的构象。仅由信号序列的羧基末端或成熟蛋白质的氨基末端的氨基酸组成的五肽在各种溶剂中没有任何优选的构象。含有来自信号序列羧基末端部分的氨基酸和前体蛋白质成熟部分的氨基末端的八肽和九肽倾向于在三氟乙醇和十二烷基硫酸钠胶束中采用β-转角构象。因此，除了信号序列羧基末端具有小侧链的氨基酸分布外，可以想象信号肽酶也识别前体蛋白质切割位点区域中的β-转角构象。
