Low complexity and disordered regions of proteins have different structural and amino acid preferences
Low complexity and disordered regions of proteins have different structural and amino acid preferences
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DOI：
10.1039/c4mb00425f
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发表时间：
2015-01-01
影响因子：
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通讯作者：
Kumar, Manish
中科院分区：
文献类型：
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作者：
Kumari, Bandana;Kumar, Ravindra;Kumar, Manish
蛋白质中大量存在低复杂性区域（LCR）或少数氨基酸的非随机区域。 LCR 传统上被认为是具有高溶剂可及性的软结构。因此，结构研究很少关注它们。然而，LCR 已被发现包含与蛋白质结构和各种重要功能相关的信息。本研究试图了解 LCR 的结构趋势。在此，我们报告了一项旨在了解 LCR 的结构趋势、溶剂可及性和氨基酸偏好的研究。结果表明LCR可能获得任何类型的二级结构；然而，螺旋经常出现，而片状很少出现。我们还发现LCR并不总是暴露在表面上。我们发现跨膜螺旋对整体螺旋含量的贡献微不足道。具有二级结构的LCR与不具有二级结构和无序蛋白质序列的LCR相比，具有不同的氨基酸富集和缺失。然而，NMR 结构的 LCR 显示出与蛋白质无序区域的组成和功能相似性。我们还注意到，与 3/4 LCR 类似，整个氨基酸不具有单一的结构类别，而是具有多个二级结构的集合，这表明它们存在于发生结构转变的位置。总体分析表明，整体蛋白质序列对LCR的结构和序列富集的影响更大，而不仅仅是局部氨基酸组成。
Low complexity regions (LCRs) or non-random regions of a few amino acids are abundantly present in proteins. LCRs are traditionally considered as floppy structures with high solvent accessibility. Thus little attention was paid to them for structural studies. However LCRs have been found to contain information relevant to protein structure and various important functions. The present study is an attempt to understand the structural trend of LCRs. Here we report a study conducted to understand the structural trend, solvent accessibility and amino acid preferences of LCRs. The results show that LCRs might attain any type of secondary structure; however, the helix is frequently seen, whereas sheets occur rarely. We also found that LCRs are not always exposed on the surface. We found insignificant contribution of trans-membrane helices to the overall helix content. The LCRs having a secondary structure have different enrichment and depletion of amino acids from LCRs without a secondary structure and disordered protein sequences. However, LCRs of NMR structures showed compositional and functional similarity to the disordered regions of proteins. We also noted that in similar to 3/4 LCRs, the entire amino acid did not have a single structural class, but rather an ensemble of more than one secondary structure, which indicates that they are found at places where structure transition occurs. Overall analysis suggests that the overall protein sequence has a greater influence on the structural and sequence enrichment rather than only the local amino acid composition of LCRs.