Hanukoglu I, Fuchs E
Cell. 1982 Nov;31(1):243-52. doi: 10.1016/0092-8674(82)90424-x.
We have determined the DNA sequence of a cloned cDNA that is complementary to the mRNA for the 50 kilodalton (kd) human epidermal keratin. This provides the first amino acid sequence for a cytoskeletal keratin. Comparison of this sequence with those of other keratins reveals an evolutionary relationship between the cytoskeletal and the microfibrillar keratins, but shows no homology to matrix or feather keratins. The 50 kd keratin shares 28%-30% homology with partial sequences of other intermediate filament proteins, which suggests that keratins may be the most distantly related members of this class of fibrous proteins. Our computer analyses predict that the 50 kd keratin contains two long alpha-helical domains separated by a cluster of helix-inhibitory residues in the middle of the protein. These findings indicate that despite major sequence divergence among intermediate filament proteins, they retain sequences compatible with secondary structural features that appear to be common to all of them.
我们已经确定了一个克隆的互补DNA（cDNA）的序列，该cDNA与50千道尔顿（kd）人表皮角蛋白的信使核糖核酸（mRNA）互补。这提供了细胞骨架角蛋白的首个氨基酸序列。将该序列与其他角蛋白的序列进行比较，揭示了细胞骨架角蛋白和微原纤维角蛋白之间的进化关系，但与基质或羽毛角蛋白没有同源性。50 kd角蛋白与其他中间丝蛋白的部分序列具有28%-30%的同源性，这表明角蛋白可能是这类纤维蛋白中关系最为疏远的成员。我们的计算机分析预测，50 kd角蛋白包含两个长的α-螺旋结构域，中间由一簇抑制螺旋的残基隔开。这些发现表明，尽管中间丝蛋白之间存在主要的序列差异，但它们保留了与所有中间丝蛋白似乎共有的二级结构特征相容的序列。
