Evolution of Fe/S cluster biogenesis in the anaerobic parasite Blastocystis.
Iron/sulfur cluster (ISC)-containing proteins are essential components of cells. In most eukaryotes, Fe/S clusters are synthesized by the mitochondrial ISC machinery, the cytosolic iron/sulfur assembly system, and, in photosynthetic species, a plastid sulfur-mobilization (SUF) system. Here we show that the anaerobic human protozoan parasite Blastocystis, in addition to possessing ISC and iron/sulfur assembly systems, expresses a fused version of the SufC and SufB proteins of prokaryotes that it has acquired by lateral transfer from an archaeon related to the Methanomicrobiales, an important lineage represented in the human gastrointestinal tract microbiome. Although components of the Blastocystis ISC system function within its anaerobic mitochondrion-related organelles and can functionally replace homologues in Trypanosoma brucei, its SufCB protein has similar biochemical properties to its prokaryotic homologues, functions within the parasite's cytosol, and is up-regulated under oxygen stress. Blastocystis is unique among eukaryotic pathogens in having adapted to its parasitic lifestyle by acquiring a SUF system from nonpathogenic Archaea to synthesize Fe/S clusters under oxygen stress.
Centre for Comparative Genomics and Evolutionary Bioinformatics, Department of Biochemistry and Molecular Biology,  Dalhousie University, Halifax, NS,  Canada B3H 4R2.
Anastasios D
AD
Tsaousis
Sandrine
S
Ollagnier de Choudens
Eleni
E
Gentekaki
Shaojun
S
Long
Daniel
D
Gaston
Alexandra
A
Stechmann
Daniel
D
Vinella
Béatrice
B
Py
Marc
M
Fontecave
Frédéric
F
Barras
Julius
J
Lukeš
Andrew J
AJ
Roger
D000693:Anaerobiosis; D000818:Animals; D005075:Biological Evolution; D016844:Blastocystis / Q000378:metabolism*; D007506:Iron-Sulfur Proteins / Q000378:metabolism*; D008969:Molecular Sequence Data; D010802:Phylogeny
D007506:Iron-Sulfur Proteins