CcNiR: Difference between revisions
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== Your Heading Here ('ccNiR') == | == Your Heading Here ('ccNiR') == | ||
<StructureSection load=' | <StructureSection load='1oah' size='500' side='left' caption='CYTOCHROME C NITRITE REDUCTASE FROM DESULFOVIBRIO DESULFURICANS ATCC 27774 (PDB entry [[1oah]])' scene=''> | ||
Cytochrome c nitrite reductase is a multicenter enzyme that uses a five-coordinated to perform the reduction of nitrite to ammonium in a six-electron transfer reaction. In the sulfate reducing bacterium Desulfovibrio desulfuricans ATCC 27774, the enzyme is purified as a NrfA2NrfH complex that houses 14 <scene name='CcNiR/Hemes/1'>hemes</scene>. <ref>pmid 14511372</ref> <ref>pmid 12618432</ref> <ref>pmid 8798514</ref> <ref>pmid 17207484</ref> <ref>pmid 20689707</ref> <ref>pmid 17207484</ref> | Cytochrome c nitrite reductase is a multicenter enzyme that uses a five-coordinated to perform the reduction of nitrite to ammonium in a six-electron transfer reaction. In the sulfate reducing bacterium Desulfovibrio desulfuricans ATCC 27774, the enzyme is purified as a NrfA2NrfH complex that houses 14 <scene name='CcNiR/Hemes/1'>hemes</scene>. <ref>pmid 14511372</ref> <ref>pmid 12618432</ref> <ref>pmid 8798514</ref> <ref>pmid 17207484</ref> <ref>pmid 20689707</ref> <ref>pmid 17207484</ref> | ||
Revision as of 11:29, 6 September 2012
Your Heading Here ('ccNiR')
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Cytochrome c nitrite reductase is a multicenter enzyme that uses a five-coordinated heme to perform the reduction of nitrite to ammonium in a six-electron transfer reaction. In the sulfate reducing bacterium Desulfovibrio desulfuricans ATCC 27774, the enzyme is purified as a NrfA4NrfH4 complex that houses 28 hemes.
The catalytic reaction occurs at a high-spin (5-coordinated) heme that is located at the pentahemic subunit NrfA which is strongly bound to its physiological electron donor, the smaller hydrophobic polypeptide tetrahemic NrfH, composed of 4 c-types hemes; in vitro, the protein complexes associate each other forming huge aggregates (min. 890 kDa). The overall haem arrangement of the NrfHA complex is quite surprising, as the NrfH haem groups are positioned non-symmetrically with respect to the two NrfA molecules.
