Blomquist M C, Hunt L T, Barker W C
Proc Natl Acad Sci U S A. 1984 Dec;81(23):7363-7. doi: 10.1073/pnas.81.23.7363.
We observed two unusual patterns of cysteine and glycine residues in transforming growth factor type 1 (TGF1); our computer search found only one other protein, the 19-kilodalton early protein of vaccinia virus, having both patterns. The sequences of epidermal growth factor (EGF) and of the light chains from several components of the blood coagulation system also have one of the patterns, but gaps are required to adjust conserved cysteine and glycine residues in the second pattern. We used several computer analyses to confirm these relationships; the 19-kilodalton protein appears to be related to TGF1 and EGF to the same degree that they are related to each other; all three are more distantly related to the coagulation factors. An evolutionary scheme is presented for these proteins. We suggest that the conservation of cysteine residues, which form the disulfide bonds present in the active EGF molecule, may extend to conservation of disulfide bonds in these other proteins. We also suggest that the structural similarities may be correlated with a protein-binding capability.
我们在转化生长因子1型（TGF1）中观察到半胱氨酸和甘氨酸残基的两种不同寻常的模式；我们的计算机检索发现只有另一种蛋白质，即痘苗病毒的19千道尔顿早期蛋白，具有这两种模式。表皮生长因子（EGF）以及血液凝固系统几个组分的轻链序列也具有其中一种模式，但需要空位来调整第二种模式中保守的半胱氨酸和甘氨酸残基。我们使用了几种计算机分析来证实这些关系；19千道尔顿蛋白与TGF1的关系似乎与TGF1和EGF之间的关系程度相同；这三者与凝血因子的关系更为疏远。本文提出了这些蛋白质的进化方案。我们认为，形成活性EGF分子中二硫键的半胱氨酸残基的保守性，可能延伸至这些其他蛋白质中二硫键的保守性。我们还认为，结构上的相似性可能与蛋白质结合能力相关。
