Journal of Molecular Evolution

, Volume 47, Issue 5, pp 557–564 | Cite as

What Amino Acid Properties Affect Protein Evolution?

  • Xuhua  Xia
  • Wen-Hsiung  Li


We studied 10 protein-coding mitochondrial genes from 19 mammalian species to evaluate the effects of 10 amino acid properties on the evolution of the genetic code, the amino acid composition of proteins, and the pattern of nonsynonymous substitutions. The 10 amino acid properties studied are the chemical composition of the side chain, two polarity measures, hydropathy, isoelectric point, volume, aromaticity, aliphaticity, hydrogenation, and hydroxythiolation. The genetic code appears to have evolved toward minimizing polarity and hydropathy but not the other seven properties. This can be explained by our finding that the presumably primitive amino acids differed much only in polarity and hydropathy, but little in the other properties. Only the chemical composition (C) and isoelectric point (IE) appear to have affected the amino acid composition of the proteins studied, that is, these proteins tend to have more amino acids with typical C and IE values, so that nonsynonymous mutations tend to result in small differences in C and IE. All properties, except for hydroxythiolation, affect the rate of nonsynonymous substitution, with the observed amino acid changes having only small differences in these properties, relative to the spectrum of all possible nonsynonymous mutations.

Key words: Polarity — Hydropathy — Isoelectric point — Aromaticity — Chemical composition — Volume — Genetic code — Protein evolution — Substitution rate 


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Copyright information

© Springer-Verlag New York Inc. 1998

Authors and Affiliations

  • Xuhua  Xia
    • 1
  • Wen-Hsiung  Li
    • 2
  1. 1.Department of Ecology and Biodiversity, University of Hong Kong, Pokfulam Road, Hong KongHK
  2. 2.Human Genetics Center, SPH, University of Texas, P.O. Box 20334, Houston TX 77225, USAUS

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