The presence of four iron-containing superoxide dismutase isozymes in Trypanosomatidae: Characterization, subcellular localization, and phylogenetic origin in Trypanosoma brucei

Autor: René Wintjens, Christophe Noël, Monique Capron, Eric Viscogliosi, Delphine Gerbod, Virginia P. Edgcomb, Cédric Yernaux, Frederik Opperdoes, Fabienne Dufernez, Mélanie Chauvenet
Rok vydání: 2006
Předmět:
Zdroj: Free Radical Biology and Medicine. 40:210-225
ISSN: 0891-5849
DOI: 10.1016/j.freeradbiomed.2005.06.021
Popis: Metalloenzymes such as the superoxide dismutases (SODs) form part of a defense mechanism that helps protect obligate and facultative aerobic organisms from oxygen toxicity and damage. Here, we report the presence in the trypanosomatid genomes of four SOD genes: soda, sodb1, sodb2, and a newly identified sodc. All four genes of Trypanosoma brucei have been cloned (Tbsods), sequenced, and overexpressed in Escherichia coli and shown to encode active dimeric FeSOD isozymes. Homology modeling of the structures of all four enzymes using available X-ray crystal structures of homologs showed that the four TbSOD structures were nearly identical. Subcellular localization using GFP-fusion proteins in procyclic insect trypomastigotes shows that TbSODB1 is mainly cytosolic, with a minor glycosomal component, TbSODB2 is mainly glycosomal with some activity in the cytosol, and TbSODA and TbSODC are both mitochondrial isozymes. Phylogenetic studies of all available trypanosomatid SODs and 106 dimeric FeSODs and closely related cambialistic dimeric SOD sequences suggest that the trypanosomatid SODs have all been acquired by more than one event of horizontal gene transfer, followed by events of gene duplication.
Databáze: OpenAIRE