Open AccessCloning and functional expression of the mitochondrial alternative oxidase of Aspergillus fumigatus and its induction by oxidative stress
Author(s) -
Magnani T.,
Soriani F.M.,
Martins V.P.,
Nascimento A.M.,
Tudella V.G.,
Curti C.,
Uyemura S.A.
Publication year - 2007
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.2007.00716.x
Subject(s) - alternative oxidase , salicylhydroxamic acid , aspergillus fumigatus , heterologous expression , menadione , oxidative stress , antimycin a , biology , reactive oxygen species , biochemistry , oxidative phosphorylation , respiratory chain , oxidase test , mitochondrion , microbiology and biotechnology , recombinant dna , gene , enzyme
Aspergillus fumigatus possesses a branched mitochondrial electron transport chain, with both cyanide‐sensitive and ‐insensitive oxygen‐consumption activities. Mitochondrial reactive oxygen species mediate signaling for alternative oxidase (AOX) expression. A 1173 bp‐long Afaox gene encoding a 40 kDa protein has been cloned and identified. Recombinant constructs containing the Afaox ORF were transformed into Escherichia coli and Saccharomyces cerevisiae for heterologous expression. In A. fumigatus , AOX activity and mRNA expression were both induced with menadione or paraquat, suggesting an important role of AOX under oxidative stress. Therefore, positive transformants showed a cyanide‐resistant and salicylhydroxamic acid‐sensitive respiration, whereas in control cells the oxygen uptake was completely inhibited after KCN addition.