In search of the prototype of nitric oxide synthase.
Recent identification of the prokaryotic genes related to the catalytic oxygenase domain of mammalian nitric oxide synthase (NOS) has led to speculations on the origins of the NO signaling network. NOS activity in eukaryotes relies on the concerted action of the oxygenase domain with an electron-donating reductase domain that is fused to it. A fused reductase domain is, however, absent in prokaryotes. Consequently, we searched bacterial genomes for homologs of the reductase domain and identified candidate genes. On the basis of genomic sequence and protein structural analysis, we here propose that sulfite reductase flavoprotein is a prototype of the mammalian NOS reductase domain and a complementing interaction partner of the bacterial NOS oxygenase protein.
Department of Bioinformatics, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany. zemojtel@biozentrum.uni-wuerzburg.de
Tomasz
T
Zemojtel
Rebecca C
RC
Wade
Thomas
T
Dandekar
D000595:Amino Acid Sequence; D000818:Animals; D030561:Databases, Nucleic Acid; D019143:Evolution, Molecular; D016680:Genome, Bacterial; D006801:Humans; D019001:Nitric Oxide Synthase / Q000235:genetics*; D050862:Oxidoreductases Acting on Sulfur Group Donors; D010802:Phylogeny; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment; D017385:Sequence Homology; D050864:Sulfite Reductase (NADPH)
D019001:Nitric Oxide Synthase; D050862:Oxidoreductases Acting on Sulfur Group Donors; D050864:Sulfite Reductase (NADPH)