Study of Completed Archaeal Genomes and Proteomes:Hypothesis of Strong Mutational AT Pressure Existed in Their Common Predecessor

作     者：Vladislav V.Khrustalev Eugene V.Barkovsky 

作者机构：Department of General ChemistryBelarussian State Medical University 

出 版 物：《Genomics, Proteomics & Bioinformatics》 (基因组蛋白质组与生物信息学报（英文版）)

年 卷 期：2010年第8卷第1期

页      面：22-32页

核心收录：

学科分类：0710[理学-生物学] 07[理学] 08[工学] 09[农学] 071007[理学-遗传学] 0901[农学-作物学] 0836[工学-生物工程] 090102[农学-作物遗传育种] 

主　　题：G+C 3GC arginine mutational pressure archaea entropy 

摘      要：The number of completely sequenced archaeal genomes has been sufficient for a large-scale bioinformatic study. We have conducted analyses for each coding region from 36 archaeal genomes using the original CGS algorithm by calculating the total GC content （G＋C）, GC content in first, second and third codon positions as well as in fourfold and twofold degenerated sites from third codon positions, levels of arginine codon usage （Arg2： AGA/G; Arg4： CGX）, levels of amino acid usage and the entropy of amino acid content distribution. In archaeal genomes with strong GC pressure, arginine is coded preferably by GC-rich Arg4 codons, whereas in most of archaeal genomes with G＋C〈0.6, arginine is coded preferably by AT-rich Arg2 codons. In the genome of Haloquadratum walsbyi, which is closely related to GC-rich archaea, GC content has decreased mostly in third codon positions, while Arg4〉〉Arg2 bias still persists. Proteomes of archaeal species carry characteristic amino acid biases： levels of isoleucine and lysine are elevated, while levels of alanine, histidine, glutamine and cytosine are relatively decreased. Numerous genomic and proteomic biases observed can be explained by the hypothesis of previously existed strong mutational AT pressure in the common predecessor of all archaea.