+ Site Statistics
+ Search Articles
+ Subscribe to Site Feeds
EurekaMag Most Shared ContentMost Shared
EurekaMag PDF Full Text ContentPDF Full Text
+ PDF Full Text
Request PDF Full TextRequest PDF Full Text
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter
Follow on LinkedInFollow on LinkedIn

+ Translate

Iron hydrogenases and the evolution of anaerobic eukaryotes

Iron hydrogenases and the evolution of anaerobic eukaryotes

Molecular Biology and Evolution 17(11): 1695-1709

Hydrogenases, oxygen-sensitive enzymes that can make hydrogen gas, are key to the function of hydrogen-producing organelles (hydrogenosomes), which occur in anaerobic protozoa scattered throughout the eukaryotic tree. Hydrogenases also play a central role in the hydrogen and syntrophic hypotheses for eukaryogenesis. Here, we show that sequences related to iron-only hydrogenases ((Fe) hydrogenases) are more widely distributed among eukaryotes than reports of hydrogen production have suggested. Genes encoding small proteins which contain conserved structural features unique to (Fe) hydrogenases were identified on all well-surveyed aerobic eukaryote genomes. Longer sequences encoding (Fe) hydrogenases also occur in the anaerobic eukaryotes Entamoeba histolytica and Spironucleus barkhanus, both of which lack hydrogenosomes. We also identified a new (Fe) hydrogenase sequence from Trichomonas vaginalis, bringing the total of (Fe) hydrogenases reported for this organism to three, all of which may function within its hydrogenosomes. Phylogenetic analysis and hypothesis testing using likelihood ratio tests and parametric bootstrapping suggest that the (Fe) hydrogenases in anaerobic eukaryotes are not monophyletic. Iron-only hydrogenases from Entamoeba, Spironucleus, and Trichomonas are plausibly monophyletic, consistent with the hypothesis that a gene for (Fe) hydrogenase was already present on the genome of the common, perhaps also anaerobic, ancestor of these phylogenetically distinct eukaryotes. Trees where the (Fe) hydrogenase from the hydrogenosomal ciliate Nyctotherus was constrained to be monophyletic with the other eukaryote sequences were rejected using a likelihood ratio test of monophyly. In most analyses, the Nyctotherus sequence formed a sister group with a (Fe) hydrogenase on the genome of the eubacterium Desulfovibrio vulgaris. Thus, it is possible that Nyctotherus obtained its hydrogenosomal (Fe) hydrogenase from a different source from Trichomonas for its hydrogenosomes. We find no support for the hypothesis that components of the Nyctotherus (Fe) hydrogenase fusion protein derive from the mitochondrial respiratory chain.

(PDF emailed within 0-6 h: $19.90)

Accession: 010885215

Download citation: RISBibTeXText

PMID: 11070057

DOI: 10.1093/oxfordjournals.molbev.a026268

Related references

Alpha proteobacterial ancestry of the [Fe-Fe]-hydrogenases in anaerobic eukaryotes. Biology Direct 11(): 34-34, 2016

Iron hydrogenases - ancient enzymes in modern eukaryotes. Trends in Biochemical Sciences 27(3): 148-153, March, 2002

Iron-sulfur proteins in anaerobic eukaryotes. Ljungdahl, Lars G , Reprint Author, Adams, Michael W , Reprint Author, Barton, Larry L, Ferry, James G, Johnson, Michael K Biochemistry and physiology of anaerobic bacteria: 113-127, 2003

Biochemistry and evolution of anaerobic energy metabolism in eukaryotes. Microbiology and Molecular Biology Reviews 76(2): 444-495, 2012

Pyruvata Ferredoxin oxidoreductase of oxymoands and evolution of anaerobic energy generating system of eukaryotes. Abstracts of the General Meeting of the American Society for Microbiology 103: R-032, 2003

Pyruvate-phosphate dikinase of oxymonads and parabasalia and the evolution of pyrophosphate-dependent glycolysis in anaerobic eukaryotes. Eukaryotic Cell 5(1): 148-154, 2006

A single eubacterial origin of eukaryotic pyruvate: ferredoxin oxidoreductase genes: implications for the evolution of anaerobic eukaryotes. Molecular Biology and Evolution 16(9): 1280-1291, 1999

Evolution of the cytosolic iron-sulfur cluster assembly machinery in Blastocystis species and other microbial eukaryotes. Eukaryotic Cell 13(1): 143-153, 2014

Genetic Diversity of Microbial Eukaryotes in Anoxic Sediment of the Saline Meromictic Lake Namako-ike (Japan): On the Detection of Anaerobic or Anoxic-tolerant Lineages of Eukaryotes. Protist 158(1): 51-64, 2006

Pentacoordinate iron complexes as functional models of the distal iron in [FeFe] hydrogenases. Chemical Communications 47(42): 11662-4, 2012

Theoretical studies on the reaction mechanisms of the nickel-iron and iron-only hydrogenases. Abstracts of Papers American Chemical Society 223(1-2): PHYS 265, 2002

Active-site models for iron hydrogenases: reduction chemistry of dinuclear iron complexes. Inorganic Chemistry 45(20): 8000-8002, 2006

Electrochemistry of Simple Organometallic Models of Iron-Iron Hydrogenases in Organic Solvent and Water. Inorganic Chemistry 55(2): 390-398, 2016

Reactivity of iron and nickel-iron-selenium hydrogenases with their oxido-reduction partner: The tetraheme cytochrome C-3. Biochemical & Biophysical Research Communications 189(2): 633-639, 1992

On the novel hydrogen activating iron sulfur center of the iron only hydrogenases. Biochimie (Paris) 68(1): 35-42, 1986