Heat shock protein 60 sequence comparisons: duplications, lateral transfer, and mitochondrial evolution.
Heat shock protein 60 sequence comparisons: duplications, lateral transfer, and mitochondrial evolution.
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DOI：
10.1073/pnas.97.21.11348
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发表时间：
2000-10
影响因子：
11.1
通讯作者：
S. Karlin;L. Brocchieri
中科院分区：
文献类型：
--
作者：
S. Karlin;L. Brocchieri
热休克蛋白60 （GroEL）是真核生物细胞器和真细菌基因组中高度表达的必需蛋白。这些伴侣蛋白已被作为追踪线粒体（Mt）基因组进化的有利标记序列。基于显著片段对比对计算的HSP60序列之间的相似性用于推断考虑GroEL功能/结构域差异的序列关联，并将α -变形杆菌谱系中普遍存在的HSP60重复与横向转移和质粒整合动力学联系起来。为10个自然群体确定了具有共识的多重排列。群体共识强化了个体序列之间的相似性对比。特别是，Mt组与经典α -变形菌群最匹配，与立克次体密切匹配，但与立克次体群埃利希氏体和东方体明显差。然而，在广泛的蛋白质序列比较中，似乎没有一致的原核生物的蛋白质序列与动物Mt基因组最一致。有可能的情况表明，核编码的HSP60（和HSP70）序列在Mt中起作用是侧向转移的结果，可能来自α -变形菌。这一假设与经典α -变形菌中存在大量重复的HSP60序列有关，而在变形菌基因组的其他分支中没有重复的HSP60序列。进化关系被不同的选择压力、趋同、可变的突变率、位点变异和横向基因转移所混淆。
Heat shock proteins 60 (GroEL) are highly expressed essential proteins in eubacterial genomes and in eukaryotic organelles. These chaperone proteins have been advanced as propitious marker sequences for tracing the evolution of mitochondrial (Mt) genomes. Similarities among HSP60 sequences based on significant segment pair alignment calculations are used to deduce associations of sequences taking into account GroEL functional/structural domain differences and to relate HSP60 duplications pervasive in alpha-proteobacterial lineages to the dynamics of lateral transfer and plasmid integration. Multiple alignments with consensuses are determined for 10 natural groups. The group consensuses sharpen the similarity contrasts among individual sequences. In particular, the Mt group matches best with the classical alpha-proteobacteria and closely with Rickettsia but significantly worse with the rickettsial groups Ehrlichia and Orientia. However, across broad protein sequence comparisons, there appears to be no consistent prokaryote whose protein sequences align best with animal Mt genomes. There are plausible scenarios indicating that the nuclear-encoded HSP60 (and HSP70) sequences functioning in Mt are results of lateral transfer and are probably derived from an alpha-proteobacterium. This hypothesis relates to the plethora of duplicated HSP60 sequences among the classical alpha-proteobacteria contrasted with no duplications of HSP60 among other clades of proteobacterial genomes. Evolutionary relations are confounded by differential selection pressures, convergence, variable mutational rates, site variability, and lateral gene transfer.