6hif
From Proteopedia
Kuenenia stuttgartiensis hydrazine dehydrogenase complex
Structural highlights
FunctionHDH_KUEST Catalyzes the four-electron oxidation of hydrazine to N2 (PubMed:21964329). The electrons derived from hydrazine oxidation may be transferred to the quinone pool and exploited to promote the generation of proton-motive force (pmf) across the anammoxosome membrane (PubMed:21964329, PubMed:23210799). Is involved in anaerobic ammonium oxidation (anammox), a biological process in which nitrite is used as the electron acceptor in the conversion of ammonium to dinitrogen gas (N2) and water; this bacterial process has a major role in the Earth's nitrogen cycle and has been estimated to synthesize up to 50% of the dinitrogen gas emitted into our atmosphere from the oceans (PubMed:21964329). Cannot oxidize hydroxylamine to NO (PubMed:21964329).[1] [2] Publication Abstract from PubMedAnaerobic ammonium oxidation (anammox) is a major process in the biogeochemical nitrogen cycle in which nitrite and ammonium are converted to dinitrogen gas and water through the highly reactive intermediate hydrazine. So far, it is unknown how anammox organisms convert the toxic hydrazine into nitrogen and harvest the extremely low potential electrons (-750 mV) released in this process. We report the crystal structure and cryo electron microscopy structures of the responsible enzyme, hydrazine dehydrogenase, which is a 1.7 MDa multiprotein complex containing an extended electron transfer network of 192 heme groups spanning the entire complex. This unique molecular arrangement suggests a way in which the protein stores and releases the electrons obtained from hydrazine conversion, the final step in the globally important anammox process. A 192-heme electron transfer network in the hydrazine dehydrogenase complex.,Akram M, Dietl A, Mersdorf U, Prinz S, Maalcke W, Keltjens J, Ferousi C, de Almeida NM, Reimann J, Kartal B, Jetten MSM, Parey K, Barends TRM Sci Adv. 2019 Apr 17;5(4):eaav4310. doi: 10.1126/sciadv.aav4310. eCollection 2019, Apr. PMID:31001586[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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