Nakashima H, Nishikawa K, Ooi T
J Biochem. 1986 Jan;99(1):153-62. doi: 10.1093/oxfordjournals.jbchem.a135454.
The folding types of 135 proteins, the three-dimensional structures of which are known, were analyzed in terms of the amino acid composition. The amino acid composition of a protein was expressed as a point in a multidimensional space spanned with 20 axes, on which the corresponding contents of 20 amino acids in the protein were represented. The distribution pattern of proteins in this composition space was examined in relation to five folding types, alpha, beta, alpha/beta, alpha + beta, and irregular type. The results show that amino acid compositions of the alpha, beta, and alpha/beta types are located in different regions in the composition space, thus allowing distinct separation of proteins depending on the folding types. The points representing proteins of the alpha + beta and irregular types, however, are widely scattered in the space, and the existing regions overlap with those of the other folding types. A simple method of utilizing the "distance" in the space was found to be convenient for classification of proteins into the five folding types. The assignment of the folding type with this method gave an accuracy of 70% in the coincidence with the experimental data.
对已知三维结构的135种蛋白质的折叠类型，依据氨基酸组成进行了分析。蛋白质的氨基酸组成以一个20维空间中的点来表示，该空间的20个轴分别代表蛋白质中20种氨基酸的相应含量。在这个组成空间中，研究了蛋白质相对于α、β、α/β、α + β和不规则型这五种折叠类型的分布模式。结果表明，α型、β型和α/β型蛋白质的氨基酸组成位于组成空间的不同区域，从而能够根据折叠类型对蛋白质进行明显区分。然而，代表α + β型和不规则型蛋白质的点在空间中广泛分散，其存在区域与其他折叠类型的区域重叠。发现一种利用空间中“距离”的简单方法便于将蛋白质分类为这五种折叠类型。用这种方法确定折叠类型与实验数据的吻合度达到了70%。
