title: Phylogenetic relationships and protein modelling revealed two distinct subfamilies of group II HKT genes between crop and model grasses.
abstract: Molecular evolution of large protein families in closely related species can provide useful insights on structural functional relationships. Phylogenetic analysis of the grass-specific group II HKT genes identified two distinct subfamilies, I and II. Subfamily II was represented in all species, whereas subfamily I was identified only in the small grain cereals and possibly originated from an ancestral gene duplication post divergence from the coarse grain cereal lineage. The core protein structures were highly analogous despite there being no more than 58% amino acid identity between members of the two subfamilies. Distinctly variable regions in known functional domains, however, indicated functional divergence of the two subfamilies. The subsets of codons residing external to known functional domains predicted signatures of positive Darwinian selection potentially identifying new domains of functional divergence and providing new insights on the structural function and relationships between protein members of the two subfamilies.
authors.affiliation: a School of Plant Biology and Institute of Agriculture, The University of Western Australia, Crawley WA 6009, Australia.|b State Agricultural Biotechnology Centre, Murdoch University, Murdoch WA 6150, Australia.
authors.forename: H A Chandima K
authors.initials: HA
authors.lastname: Ariyarathna
authors.affiliation: b State Agricultural Biotechnology Centre, Murdoch University, Murdoch WA 6150, Australia.|c Department of Agriculture and Food Western Australia, 3 Baron Hay Ct, South Perth WA 6151, Australia.
authors.forename: Michael G
authors.initials: MG
authors.lastname: Francki
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D003062:Codon; D018556:Crops, Agricultural / Q000235:genetics / Q000378:metabolism; D018076:DNA, Complementary / Q000235:genetics; D019143:Evolution, Molecular; D020440:Gene Duplication; D017343:Genes, Plant; D005810:Multigene Family / Q000235:genetics*; D012275:Oryza / Q000235:genetics / Q000378:metabolism; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D006109:Poaceae / Q000235:genetics* / Q000378:metabolism; D027961:Potassium-Hydrogen Antiporters / Q000235:genetics* / Q000378:metabolism; D017434:Protein Structure, Tertiary; D012641:Selection, Genetic; D016415:Sequence Alignment; D014908:Triticum / Q000235:genetics / Q000378:metabolism
chemical_list: D003062:Codon; D018076:DNA, Complementary; D010940:Plant Proteins; D027961:Potassium-Hydrogen Antiporters
keywords: HKT subfamilies; domaines fonctionnels; duplication génique; functional domains; gene duplication; positive Darwinian selection; protein structure; sous-familles de HKT; structure de protéines; sélection darwinienne positive