ZHAW Life Sciences und Facility Management, Applied Computational Genomics, 8820 Wädenswil, Switzerland.
Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland.
Genes (Basel). 2020 Apr 9;11(4):407. doi: 10.3390/genes11040407.
Protein tandem repeats (TRs) are often associated with immunity-related functions and diseases. Since that last census of protein TRs in 1999, the number of curated proteins increased more than seven-fold and new TR prediction methods were published. TRs appear to be enriched with intrinsic disorder and vice versa. The significance and the biological reasons for this association are unknown. Here, we characterize protein TRs across all kingdoms of life and their overlap with intrinsic disorder in unprecedented detail. Using state-of-the-art prediction methods, we estimate that 50.9% of proteins contain at least one TR, often located at the sequence flanks. Positive linear correlation between the proportion of TRs and the protein length was observed universally, with Eukaryotes in general having more TRs, but when the difference in length is taken into account the difference is quite small. TRs were enriched with disorder-promoting amino acids and were inside intrinsically disordered regions. Many such TRs were homorepeats. Our results support that TRs mostly originate by duplication and are involved in essential functions such as transcription processes, structural organization, electron transport and iron-binding. In viruses, TRs are found in proteins essential for virulence.
蛋白质串联重复（TR）通常与免疫相关功能和疾病有关。自 1999 年最后一次对蛋白质 TR 进行普查以来，经过注释的蛋白质数量增加了七倍以上，并且新的 TR 预测方法也已发布。TR 似乎富含固有无序性，反之亦然。这种关联的意义和生物学原因尚不清楚。在这里，我们详细描述了所有生命领域的蛋白质 TR 及其与固有无序性的重叠。使用最先进的预测方法，我们估计至少有 50.9%的蛋白质含有至少一个 TR，通常位于序列侧翼。普遍观察到 TR 比例与蛋白质长度之间存在正线性相关性，一般来说真核生物的 TR 更多，但当考虑到长度差异时，差异非常小。TR 富含促进无序的氨基酸，并且位于固有无序区域内。许多这样的 TR 是同重复。我们的结果支持 TR 主要通过复制产生，并参与转录过程、结构组织、电子传递和铁结合等基本功能。在病毒中，TR 存在于对毒力至关重要的蛋白质中。
