title: Horizontal gene transfer from Eukarya to bacteria and domain shuffling: the alpha-amylase model.
abstract: Alpha-amylases are present in all kingdoms of the living world. Despite strong conservation of the tertiary structure, only a few amino acids are conserved in interkingdom comparisons. Animal alpha-amylases are characterized by several typical motifs and biochemical properties. A few cases of such alpha-amylases have been previously reported in some eubacterial species. We screened the bacterial genomes available in the sequence databases for new occurrences of animal-like alpha-amylases. Three novel cases were found, which belong to unrelated bacterial phyla: Chloroflexus aurantiacus, Microbulbifer degradans, and Thermobifida fusca. All the animal-like alpha-amylases in Bacteria probably result from repeated horizontal gene transfer from animals. The M. degradans genome also contains bacterial-type and plant-type alpha-amylases in addition to the animal-type one. Thus, this species exhibits alpha-amylases of animal, plant, and bacterial origins. Moreover, the similarities in the extra C-terminal domains (different from both the alpha-amylase domain C and the starch-binding domain), when present, also suggest interkingdom as well as intragenomic shuffling.
authors.affiliation: UPR 9034 Populations, Génétique et Evolution, CNRS, 91198, Gif sur Yvette cedex, France. jldl@pge.cnrs-gif.fr
authors.forename: J-L
authors.initials: JL
authors.lastname: Da Lage
authors.forename: G
authors.initials: G
authors.lastname: Feller
authors.forename: S
authors.initials: S
authors.lastname: Janecek
mesh_terms: D000595:Amino Acid Sequence; D001419:Bacteria / Q000235:genetics*; D041861:Chloroflexus / Q000201:enzymology / Q000235:genetics*; D005057:Eukaryotic Cells / Q000201:enzymology; D005658:Fungi / Q000145:classification / Q000235:genetics; D020563:Gammaproteobacteria / Q000201:enzymology / Q000235:genetics*; D018014:Gene Transfer Techniques; D016680:Genome, Bacterial; D006094:Gram-Positive Bacteria / Q000201:enzymology / Q000235:genetics*; D008969:Molecular Sequence Data; D010802:Phylogeny; D010944:Plants / Q000235:genetics*; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014162:Transfection; D015003:Yeasts / Q000145:classification / Q000235:genetics; D000516:alpha-Amylases / Q000737:chemistry / Q000235:genetics*
chemical_list: D000516:alpha-Amylases