Impacto do erro translacional induzido e do enovelamento livre de erro na taxa da evolução de proteína

domingo, outubro 31, 2010

Molecular Systems Biology 6 Article number: 421 doi:10.1038/msb.2010.78
Published online: 19 October 2010
Citation: Molecular Systems Biology 6:421

Impact of translational error-induced and error-free misfolding on the rate of protein evolution

Jian-Rong Yang1,2, Shi-Mei Zhuang1 & Jianzhi Zhang2

Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, PR China
Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA

Correspondence to: Jianzhi Zhang2 Department of Ecology and Evolutionary Biology, University of Michigan, 1075 Natural Science Building, 830 North University Avenue, Ann Arbor, MI 48109, USA. Tel.: +1 734 763 0527; Fax: +1 734 763 0544; Email:

Received 11 May 2010; Accepted 31 August 2010; Published online 19 October 2010

What determines the rate of protein evolution is a fundamental question in biology. Recent genomic studies revealed a surprisingly strong anticorrelation between the expression level of a protein and its rate of sequence evolution. This observation is currently explained by the translational robustness hypothesis in which the toxicity of translational error-induced protein misfolding selects for higher translational robustness of more abundant proteins, which constrains sequence evolution. However, the impact of error-free protein misfolding has not been evaluated. We estimate that a non-negligible fraction of misfolded proteins are error free and demonstrate by a molecular-level evolutionary simulation that selection against protein misfolding results in a greater reduction of error-free misfolding than error-induced misfolding. Thus, an overarching protein-misfolding-avoidance hypothesis that includes both sources of misfolding is superior to the translational robustness hypothesis. We show that misfolding-minimizing amino acids are preferentially used in highly abundant yeast proteins and that these residues are evolutionarily more conserved than other residues of the same proteins. These findings provide unambiguous support to the role of protein-misfolding-avoidance in determining the rate of protein sequence evolution.

Molecular Systems Biology 6: 421; published online 19 October 2010; doi:10.1038/msb.2010.78

Subject Categories: simulation and data analysis; proteins

Keywords: evolutionary rate; expression level; mistranslation; protein misfolding




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