A set of 24 647 nonhomologous protein sequences was examined. A pentapeptide occurrence profile was constructed for each sequence and hierarchically organized elements of various sizes were detected in each profile by a special mathematical method. Correlations between the hierarchical elements were studied. A total of 11 levels of protein organization with elements ranging from 7 to 56 amino-acid residues were found in the protein sequence set. The organization levels were assumed to correspond to super-secondary structure elements of different topologies.

中文翻译：

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蛋白质序列的层次组织水平：熵特征分析

检查了一组24 647个非同源蛋白质序列。为每个序列构建一个五肽出现图谱，并通过特殊的数学方法在每个图谱中检测到各种大小的分层组织元素。研究了层次元素之间的相关性。在该蛋白质序列集中发现了总共11个水平的蛋白质组织，其中7至56个氨基酸残基不等。假定组织级别对应于不同拓扑的超二级结构元素。