White S H, Jacobs R E
Department of Physiology and Biophysics, University of California, Irvine 92717.
Biophys J. 1990 Apr;57(4):911-21. doi: 10.1016/S0006-3495(90)82611-4.
We consider in this paper the statistical distribution of hydrophobic residues along the length of protein chains. For this purpose we used a binary hydrophobicity scale which assigns hydrophobic residues a value of one and non-hydrophobes a value of zero. The resulting binary sequences are tested for randomness using the standard run test. For the majority of the 5,247 proteins examined, the distribution of hydrophobic residues along a sequence cannot be distinguished from that expected for a random distribution. This suggests that (a) functional proteins may have originated from random sequences, (b) the folding of proteins into compact structures may be much more permissive with less sequence specificity than previously thought, and (c) the clusters of hydrophobic residues along chains which are revealed by hydrophobicity plots are a natural consequence of a random distribution and can be conveniently described by binomial statistics.
在本文中，我们研究了蛋白质链长度上疏水残基的统计分布。为此，我们使用了一种二元疏水性量表，该量表将疏水残基赋值为1，非疏水残基赋值为0。使用标准游程检验对所得的二元序列进行随机性测试。对于所检测的5247种蛋白质中的大多数而言，序列中疏水残基的分布与随机分布预期的分布无法区分。这表明：（a）功能性蛋白质可能起源于随机序列；（b）蛋白质折叠成紧密结构时，其序列特异性可能比之前认为的要低得多，限制更少；（c）疏水性图谱所揭示的沿链疏水残基簇是随机分布的自然结果，并且可以用二项式统计方便地描述。
