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Both human ferredoxins equally efficiently rescue ferredoxin deficiency in T rypanosoma brucei
Author(s) -
Changmai Piya,
Horáková Eva,
Long Shaojun,
ČernotíkováStříbrná Eva,
McDonald Lindsay M.,
Bontempi Esteban J.,
Lukeš Julius
Publication year - 2013
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/mmi.12264
Subject(s) - ferredoxin , biology , biogenesis , trypanosoma brucei , mitochondrion , microbiology and biotechnology , gene , function (biology) , genome , genetics , biochemistry , enzyme
Summary Ferredoxins are highly conserved proteins that function universally as electron transporters. They not only require Fe ‐ S clusters for their own activity, but are also involved in Fe ‐ S formation itself. We identified two homologues of ferredoxin in the genome of the parasitic protist T rypanosoma brucei and named them Tb FdxA and Tb FdxB . Tb FdxA protein, which is homologous to other eukaryotic mitochondrial ferredoxins, is essential in both the procyclic (= insect‐transmitted) and bloodstream (mammalian) stage, but is more abundant in the active mitochondrion of the former stage. Depletion of Tb FdxA caused disruption of Fe ‐ S cluster biogenesis and lowered the level of intracellular haem. However, Tb FdxB , which is present exclusively within kinetoplastid flagellates, was non‐essential for the procyclic stage, and double knock‐down with Tb FdxA showed this was not due to functional redundancy between the two homologues. Heterologous expressions of human orthologues HsFdx 1 and HsFdx 2 fully rescued the growth and Fe ‐ S ‐dependent enzymatic activities of Tb FdxA knock‐down. In both cases, the genuine human import signals allowed efficient import into the T . brucei mitochondrion. Given the huge evolutionary distance between trypanosomes and humans, ferredoxins clearly have ancestral and highly conserved function in eukaryotes and both human orthologues have retained the capacity to participate in Fe ‐ S cluster assembly.