title: A model of globin evolution.
abstract: Putative globins have been identified in 426 bacterial, 32 Archaeal and 67 eukaryote genomes. Among these sequences are the hitherto unsuspected presence of single domain sensor globins within Bacteria, Fungi, and a Euryarchaeote. Bayesian phylogenetic trees suggest that their occurrence in the latter two groups could be the result of lateral gene transfer from Bacteria. Iterated psiblast searches based on groups of globin sequences indicate that bacterial flavohemoglobins are closer to metazoan globins than to the other two lineages, the 2-over-2 globins and the globin-coupled sensors. Since Bacteria is the only kingdom to have all the subgroups of the three globin lineages, we propose a working model of globin evolution based on the assumption that all three lineages originated and evolved only in Bacteria. Although the 2-over-2 globins and the globin-coupled sensors recognize flavohemoglobins, there is little recognition between them. Thus, in the first stage of globin evolution, we favor a flavohemoglobin-like single domain protein as the ancestral globin. The next stage comprised the splitting off to single domain 2-over-2 and sensor-like globins, followed by the covalent addition of C-terminal domains resulting in the chimeric flavohemoglobins and globin-coupled sensors. The last stage encompassed the lateral gene transfers of some members of the three globin lineages to specific groups of Archaea and Eukaryotes.
authors.affiliation: Department of Biochemistry and Molecular Biology, Wayne State University School of Medicine, Detroit, MI 48201, USA. svinogra@med.wayne.edu
authors.forename: Serge N
authors.initials: SN
authors.lastname: Vinogradov
authors.forename: David
authors.initials: D
authors.lastname: Hoogewijs
authors.forename: Xavier
authors.initials: X
authors.lastname: Bailly
authors.forename: Kenji
authors.initials: K
authors.lastname: Mizuguchi
authors.forename: Sylvia
authors.initials: S
authors.lastname: Dewilde
authors.forename: Luc
authors.initials: L
authors.lastname: Moens
authors.forename: Jacques R
authors.initials: JR
authors.lastname: Vanfleteren
mesh_terms: D000818:Animals; D001105:Archaea / Q000145:classification / Q000235:genetics; D001419:Bacteria / Q000145:classification / Q000235:genetics; D019295:Computational Biology / Q000379:methods; D030561:Databases, Nucleic Acid; D005057:Eukaryotic Cells / Q000378:metabolism; D019143:Evolution, Molecular; D005914:Globins / Q000235:genetics*; D008957:Models, Genetic; D010802:Phylogeny; D013997:Time Factors
chemical_list: D005914:Globins