厌氧铵氧化的分子机制

LETTERdoi:10.1038/nature10453MolecularmechanismofanaerobicammoniumoxidationBoranKartal1,WouterJ.Maalcke1,NaomiM.deAlmeida1,IrinaCirpus1,JoleinGloerich2,WimGeerts1,HuubJ.M.OpdenCamp1,HarryR.Harhangi1,EvaM.Janssen-Megens3,Kees-JanFrancoijs3,HendrikG.Stunnenberg3,JanT.Keltjens1,MikeS.M.Jetten1,4&MarcStrous1,5Twodistinctmicrobialprocesses,denitrificationandanaerobicammoniumoxidation(anammox),areresponsibleforthereleaseoffixednitrogenasdinitrogengas(N2)totheatmosphere1–4.Denitrificationhasbeenstudiedforover100yearsanditsinter-mediatesandenzymesarewellknown5.Eventhoughanammoxisakeybiogeochemicalprocessofequalimportance,itsmolecularmechanismisunknown,butitwasproposedtoproceedthroughhydrazine(N2H4)6,7.HereweshowthatN2H4isproducedfromtheanammoxsubstratesammoniumandnitriteandthatnitricoxide(NO)isthedirectprecursorofN2H4.WeresolvedthegenesandproteinscentraltoanammoxmetabolismandpurifiedthekeyenzymesthatcatalyseN2H4synthesisanditsoxidationtoN2.Theseresultspresentanewbiochemicalreactionforging