Amino acid sequence coevolution in the insect bursicon ligand-receptor system

作者：Hughes Austin L^*

来源：Molecular Phylogenetics and Evolution, 2012, 63(3): 617-624.

DOI：10.1016/j.ympev.2012.02.003

• Bursicon
• Convergent evolution
• Functional constraint
• Parallel evolution
• Protein-protein interactions

The pattern of amino acid residue replacement in the components of the bursicon signaling system (involving the BURS alpha/BURS beta heterodimer and its receptor BURSrec) was reconstructed across a phylogeny of 17 insect species, in order to test for the co-occurrence of replacements at sets of individual sites. Sets of three or more branches with perfectly concordant changes occurred to a greater extent than expected by chance, given the observed level of amino acid change. The latter sites (SPC sites) were found to have distinctive characteristics: (1) the mean number of changes was significantly lower at SPC sites than that at other sites with multiple changes; (2) SPC sites had a significantly greater tendency toward parallel amino acid changes than other sites with multiple changes, but no greater tendency toward convergent changes; and (3) parallel changes tended to involve relatively similar amino acids, as indicated by relatively low mean chemical distances. The results implicated functional constraint, permitting only a limited subset of amino acids in a given site, as a major factor in causing both parallel amino acid replacement and coordinated amino acid changes in different sites of the same protein and of interacting proteins in this system.

• 出版日期2012-6