title: Phylogenetic distribution of catalase-peroxidases: are there patches of order in chaos?
abstract: Hydrogen peroxide features in many biological oxidative processes and must be continuously degraded enzymatically either via a catalatic or a peroxidatic mechanism. For this purpose ancestral bacteria evolved a battery of different heme and non-heme enzymes, among which heme-containing catalase-peroxidases (CP) are one of the most widespread representatives. They are unique since they can follow both H(2)O(2)-degrading mechanisms, the catalase activity being clearly dominant. With the fast increasing amount of genomic data available, we were able to perform an extensive search for CP and found almost 300 sequences covering a large range of microorganisms. Most of them were encoded by bacterial genomes, but we could also find some in eukaryotic organisms other than fungi, which has never been shown until now. Our screen also reveals that approximately 60% of the bacteria do not possess CP genes. Chaotic distribution among species and incongruous phylogenetic reconstruction indicated existence of numerous lateral gene transfers in addition to duplication events and regular speciation. The results obtained show an impressively complex gene transmission pattern, and give some new insights about the role of CP and the origin of life on earth. Finally, we propose for the first time bacterial candidates that may have participated in the transfer of CP from bacteria to eukaryotes.
authors.affiliation: Laboratoire de Physiologie Végétale, Université de Genève, Quai Ernest-Ansermet 30, Geneva 4, Switzerland.
authors.forename: Filippo
authors.initials: F
authors.lastname: Passardi
authors.forename: Marcel
authors.initials: M
authors.lastname: Zamocky
authors.forename: Jocelyne
authors.initials: J
authors.lastname: Favet
authors.forename: Christa
authors.initials: C
authors.lastname: Jakopitsch
authors.forename: Claude
authors.initials: C
authors.lastname: Penel
authors.forename: Christian
authors.initials: C
authors.lastname: Obinger
authors.forename: Christophe
authors.initials: C
authors.lastname: Dunand
mesh_terms: D000818:Animals; D001419:Bacteria / Q000201:enzymology / Q000235:genetics; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D020134:Catalytic Domain; D005057:Eukaryotic Cells; D022761:Gene Transfer, Horizontal; D005798:Genes, Bacterial; D044404:Genomic Islands; D008958:Models, Molecular; D010544:Peroxidases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D010802:Phylogeny; D013045:Species Specificity; D013482:Superoxide Dismutase / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D010544:Peroxidases; C081610:catalase-peroxidase, bacteria; D013482:Superoxide Dismutase