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The tetraheme cytochrome c NrfH is required to anchor the cytochrome c nitrite reductase (NrfA) in the membrane of Wolinella succinogenes.

Simon, J. ; Pisa, R. ; Stein, T. ; Eichler, R. ; Klimmek, O. ; Gross, R. (2001)
The tetraheme cytochrome c NrfH is required to anchor the cytochrome c nitrite reductase (NrfA) in the membrane of Wolinella succinogenes.
In: European journal of biochemistry / FEBS, 268 (22)
Artikel, Bibliographie

Kurzbeschreibung (Abstract)

The electron-transport chain that catalyzes nitrite respiration with formate in Wolinella succinogenes consists of formate dehydrogenase, menaquinone and the nitrite reductase complex. The latter catalyzes nitrite reduction by menaquinol and is made up of NrfA and NrfH, two c-type cytochromes. NrfA is the catalytic subunit; its crystal structure is known. NrfH belongs to the NapC/NirT family of membrane-bound c-type cytochromes and mediates electron transport between menaquinol and NrfA. It is demonstrated here by MALDI MS that four heme groups are attached to NrfH. A Delta nrfH deletion mutant of W. succinogenes was constructed by replacing the nrfH gene with a kanamycin-resistance gene cartridge. This mutant did not form the NrfA protein, probably because of a polar effect of the mutation on nrfA expression. The nrfHAIJ gene cluster was restored by integration of an nrfH-containing plasmid into the genome of the Delta nrfH mutant. The resulting strain had wild-type properties with respect to growth by nitrite respiration and nitrite reductase activity. A mutant (stopH) that contained the nrfHAIJ locus with nrfH modified by two artificial stop codons near its 5' end produced wild-type amounts of NrfA in the absence of the NrfH protein. NrfA was located exclusively in the soluble cell fraction of the stopH mutant, indicating that NrfH acts as the membrane anchor of the NrfHA complex in wild-type bacteria. The stopH mutant did not grow by nitrite respiration and did not catalyze nitrite reduction by formate, indicating that the electron transport is strictly dependent on NrfH. The NrfH protein seems to be an unusual member of the NapC/NirT family as it forms a stable complex with its redox partner protein NrfA.

Typ des Eintrags: Artikel
Erschienen: 2001
Autor(en): Simon, J. ; Pisa, R. ; Stein, T. ; Eichler, R. ; Klimmek, O. ; Gross, R.
Art des Eintrags: Bibliographie
Titel: The tetraheme cytochrome c NrfH is required to anchor the cytochrome c nitrite reductase (NrfA) in the membrane of Wolinella succinogenes.
Sprache: Englisch
Publikationsjahr: 2001
Titel der Zeitschrift, Zeitung oder Schriftenreihe: European journal of biochemistry / FEBS
Jahrgang/Volume einer Zeitschrift: 268
(Heft-)Nummer: 22
Kurzbeschreibung (Abstract):

The electron-transport chain that catalyzes nitrite respiration with formate in Wolinella succinogenes consists of formate dehydrogenase, menaquinone and the nitrite reductase complex. The latter catalyzes nitrite reduction by menaquinol and is made up of NrfA and NrfH, two c-type cytochromes. NrfA is the catalytic subunit; its crystal structure is known. NrfH belongs to the NapC/NirT family of membrane-bound c-type cytochromes and mediates electron transport between menaquinol and NrfA. It is demonstrated here by MALDI MS that four heme groups are attached to NrfH. A Delta nrfH deletion mutant of W. succinogenes was constructed by replacing the nrfH gene with a kanamycin-resistance gene cartridge. This mutant did not form the NrfA protein, probably because of a polar effect of the mutation on nrfA expression. The nrfHAIJ gene cluster was restored by integration of an nrfH-containing plasmid into the genome of the Delta nrfH mutant. The resulting strain had wild-type properties with respect to growth by nitrite respiration and nitrite reductase activity. A mutant (stopH) that contained the nrfHAIJ locus with nrfH modified by two artificial stop codons near its 5' end produced wild-type amounts of NrfA in the absence of the NrfH protein. NrfA was located exclusively in the soluble cell fraction of the stopH mutant, indicating that NrfH acts as the membrane anchor of the NrfHA complex in wild-type bacteria. The stopH mutant did not grow by nitrite respiration and did not catalyze nitrite reduction by formate, indicating that the electron transport is strictly dependent on NrfH. The NrfH protein seems to be an unusual member of the NapC/NirT family as it forms a stable complex with its redox partner protein NrfA.

Fachbereich(e)/-gebiet(e): 10 Fachbereich Biologie > Microbial Energy Conversion and Biotechnology
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10 Fachbereich Biologie
Hinterlegungsdatum: 07 Dez 2010 15:10
Letzte Änderung: 05 Mär 2013 09:42
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