The NifZ accessory protein has an equivalent function in maturation of both nitrogenase MoFe protein P-clusters

dc.contributor.authorJimenez-Vicente, Emilioen
dc.contributor.authorYang, Zhi-Yongen
dc.contributor.authorDel Campo, Julia S. Martinen
dc.contributor.authorCash, Valerie L.en
dc.contributor.authorSeefeldt, Lance C.en
dc.contributor.authorDean, Dennis R.en
dc.contributor.departmentBiochemistryen
dc.date.accessioned2019-08-29T14:23:42Zen
dc.date.available2019-08-29T14:23:42Zen
dc.date.issued2019-04-19en
dc.description.abstractThe Mo-dependent nitrogenase comprises two interacting components called the Fe protein and the MoFe protein. The MoFe protein is an (22) heterotetramer that harbors two types of complex metalloclusters, both of which are necessary for N-2 reduction. One type is a 7Fe-9S-Mo-C-homocitrate species designated FeMo-cofactor, which provides the N-2-binding catalytic site, and the other is an 8Fe-7S species designated the P-cluster, involved in mediating intercomponent electron transfer to FeMo-cofactor. The MoFe protein's catalytic partner, Fe protein, is also required for both FeMo-cofactor formation and the conversion of an immature form of P-clusters to the mature species. This latter process involves several assembly factors, NafH, NifW, and NifZ, and precedes FeMo-cofactor insertion. Here, using various protein affinity-based purification methods as well as in vivo, EPR spectroscopy, and MALDI measurements, we show that several MoFe protein species accumulate in a NifZ-deficient background of the nitrogen-fixing microbe Azotobacter vinelandii. These included fully active MoFe protein replete with FeMo-cofactor and mature P-cluster, inactive MoFe protein having no FeMo-cofactor and only immature P-cluster, and partially active MoFe protein having one -unit with a FeMo-cofactor and mature P-cluster and the other -unit with no FeMo-cofactor and immature P-cluster. Also, NifW could associate with MoFe protein having immature P-clusters and became dissociated upon P-cluster maturation. Furthermore, both P-clusters could mature in vitro without NifZ. These findings indicate that NifZ has an equivalent, although not essential, function in the maturation of both P-clusters contained within the MoFe protein.en
dc.description.notesMass spectrometry resources used in this work are maintained in part through funding by the Fralin Life Science Institute, the Agricultural Experiment Station Hatch Program, and the McIntire-Stennis Program at Virginia Tech and are managed by Richard F. Helm.en
dc.description.sponsorshipFralin Life Science Institute; Agricultural Experiment Station Hatch Program; McIntire-Stennis Program at Virginia Techen
dc.format.mimetypeapplication/pdfen
dc.identifier.doihttps://doi.org/10.1074/jbc.RA119.007905en
dc.identifier.eissn1083-351Xen
dc.identifier.issue16en
dc.identifier.pmid30846561en
dc.identifier.urihttp://hdl.handle.net/10919/93299en
dc.identifier.volume294en
dc.language.isoenen
dc.rightsCreative Commons Attribution 4.0 Internationalen
dc.rights.urihttp://creativecommons.org/licenses/by/4.0/en
dc.subjectnitrogenaseen
dc.subjectnitrogen fixationen
dc.subjectmetalloenzymeen
dc.subjectnitrogen metabolismen
dc.subjectiron-sulfur proteinen
dc.subjectAzotobacter vinelandiien
dc.subjectFeMo-cofactoren
dc.subjectNifWen
dc.subjectNifZen
dc.subjectP-clusteren
dc.subjectmaturationen
dc.titleThe NifZ accessory protein has an equivalent function in maturation of both nitrogenase MoFe protein P-clustersen
dc.title.serialJournal of Biological Chemistryen
dc.typeArticle - Refereeden
dc.type.dcmitypeTexten

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