COMPUTER ANALYSIS OF LOW-COMPLEXITY AMINO ACID SEQUENCES

这个项目的目标是定义，分类和分析，使用 计算分析，蛋白质序列的所有片段 低复杂度。 这些包括残基簇， 主要是一种或几种氨基酸类型，其通常含有 这些的均聚物束或镶嵌物、非周期性图案和截面 低周期重复。这些片段的丰度 数据库已确定，其属性与 生物学功能和蛋白质结构，动力学和 组装件. a.局部成分的不同形式定义 复杂度被用来对低复杂度进行无偏识别 在不同的严格程度上。 算法经过改进， (a)选择用于进一步研究的片段，以及（B）过滤掉非信息性片段 在数据库搜索之前。 自动化的新方法 低复杂度序列的分类和邻近已经被 开发B。Ababolition和生物学特性：约25% 蛋白质数据库中的残基是在组成上有偏差的片段中 （包括一些已知的长非球状区域）和大约55% 含有一个或多个这样的片段。 分散在低- 复杂序列在许多真核生物中特别丰富， 在形态发生和胚胎发育中起关键作用的蛋白质， 加工、转录调控、信号转导和 细胞和细胞外结构的完整性。C.结构， 动力学和相互作用：有限的结构信息 对于蛋白质的低复杂性区域， 非球形且多态或移动的。该项目突出了 低复杂性蛋白质高丰度和生物学重要性 片段，并强调相对缺乏知识，其分子 结构和动力学。 低复杂度的片段显然没有 紧凑的结构和动力学，这是必要的生物 功能新的计算机方法在消除许多 序列数据库搜索和比对分析中的伪影。

The goal of this project is to define, classify and analyze, using computational analysis, all segments of protein sequences of improbably low compositional complexity. These include residue clusters of predominantly one or a few amino acid types, which commonly contain homopolymeric tracts or mosaics of these, aperiodic patterns and sections of low-period repeats. The abundance of these segments in sequence databases has been determined and their properties are being related to evidence of biological functions and protein structure, dynamics and assembly. A. Different formal definitions of local compositional complexity were used to make unbiased identification of low-complexity segments, at different levels of stringency. Algorithms were refined to (a) select segments for further study and (b) filter out non-informative segments prior to database searches. New methods for automated classification and neighboring of low-complexity sequences have been developed. B. Abundance and biological properties: Approximately 25% of the residues in protein databases are in compositionally biased segments (including some known long non-globular regions) and approximately 55% of proteins contain one or more such segments. Interspersed low- complexity sequences are particularly abundant in many eukaryotic proteins crucial in morphogenesis and embryonic development, RNA processing, transcriptional regulation, signal transduction and aspects of cellular and extracellular structural integrity. C. Structures, dynamics and interactions: The limited structuralinformation available for low-complexity regions of proteins indicates that they are generally non-globular and polymorphic or mobile. The project has highlighted the high abundance and biological importance of low-complexity protein segments and emphasized the relative lack of knowledge of their molecular structure and dynamics. Low complexity segments evidently have non- compact structures and dynamics which are necessary for biological function. The new computer methods are valuable in eliminating many artefacts in sequence database searches and alignment analysis.