Gough K H, Inglis A S, Crewther W G
Biochem J. 1978 Aug 1;173(2):373-85. doi: 10.1042/bj1730373.
The amino acid sequence of a type-I helical segment from the low-sulphur protein (S-carboxymethylkerateine-A) of wool was determined by combining automatic and manual-sequencing data. Whereas in the type-II helical segment most of the cationic groups occur in pairs, 11 of the 22 anionic residues in the sequence of the type-I segment were situated next to a second anionic residue. This suggests possible interactions between type-I and type-II helical segments in alpha-keratin. As observed with the sequence of a type-II helical segment a model constructed on 3.6 residues per turn of helix shows a line of hydrophobic residues along the helix, thereby supporting the physicochemical evidence that the molecule is predominantly helical and forms part of a coiled-coil structure. Examination of the sequence data by predictive methods indicates the possibilty of extensive sections of alpha-helix interspersed with discontinuities. The molecule contains a number of regions with peptide sequences identical with those found by other workers after enzymic digestion of fractions from oxidized wool.
通过整合自动测序和手动测序数据，确定了羊毛低硫蛋白（S-羧甲基角蛋白-A）中一个I型螺旋片段的氨基酸序列。在II型螺旋片段中，大多数阳离子基团成对出现，而在I型片段序列的22个阴离子残基中，有11个与第二个阴离子残基相邻。这表明α-角蛋白中I型和II型螺旋片段之间可能存在相互作用。正如在II型螺旋片段序列中所观察到的那样，基于每圈螺旋3.6个残基构建的模型显示，沿着螺旋有一排疏水残基，从而支持了该分子主要为螺旋结构并构成卷曲螺旋结构一部分的物理化学证据。通过预测方法对序列数据的检查表明，α-螺旋的广泛区域可能穿插有间断。该分子包含许多肽序列区域，这些区域与其他研究人员在对氧化羊毛组分进行酶消化后发现的序列相同。
