CcNiR: Difference between revisions
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<StructureSection load='1oah' size='500' side='left' caption='CYTOCHROME C NITRITE REDUCTASE FROM DESULFOVIBRIO DESULFURICANS ATCC 27774 (PDB entry [[1oah]])' scene=''> | <StructureSection load='1oah' size='500' side='left' caption='CYTOCHROME C NITRITE REDUCTASE FROM DESULFOVIBRIO DESULFURICANS ATCC 27774 (PDB entry [[1oah]])' scene=''> | ||
The cytochrome 𝑐 nitrite reductase (ccNiR) from Desulfovibrio desulfuricans ATCC 27774 is able to reduce nitrite to ammonia in a six-electron transfer reaction. | The cytochrome 𝑐 nitrite reductase (ccNiR) from Desulfovibrio desulfuricans ATCC 27774 is able to reduce nitrite to ammonia in a six-electron transfer reaction. | ||
NO2- + 4 H+ + 6 ferricytochrome c = NH4+ + 6 ferrocytochrome c + 2 H2O | |||
The physiological form of the enzyme is believed to be a double trimer of 2 NrfA and 1 NrfH subunits. The catalytic subunit NrfA is a periplasmic membrane-associated pentaheme cytochrome c where the short distances between <scene name='CcNiR/Hemes3/1'>hemes</scene> allow a fast and efficient electron transfer. The active site has been reported as an unusual lysine-coordinated high-spin heme. NrfH is a small membrane-bound cytochrome comprising four c-type heme groups and it serves a double purpose. On one hand, it anchors the catalytic subunits to the membrane. On the other hand, it serves as a quinol oxidase, transferring electrons from the quinone pool to the catalytic subunits. <ref>pmid 14511372</ref> <ref>pmid 12618432</ref> <ref>pmid 8798514</ref> <ref>pmid 17207484</ref> <ref>pmid 20689707</ref> <ref>pmid 17207484</ref> | The physiological form of the enzyme is believed to be a double trimer of 2 NrfA and 1 NrfH subunits. The catalytic subunit NrfA is a periplasmic membrane-associated pentaheme cytochrome c where the short distances between <scene name='CcNiR/Hemes3/1'>hemes</scene> allow a fast and efficient electron transfer. The active site has been reported as an unusual lysine-coordinated high-spin heme. NrfH is a small membrane-bound cytochrome comprising four c-type heme groups and it serves a double purpose. On one hand, it anchors the catalytic subunits to the membrane. On the other hand, it serves as a quinol oxidase, transferring electrons from the quinone pool to the catalytic subunits. <ref>pmid 14511372</ref> <ref>pmid 12618432</ref> <ref>pmid 8798514</ref> <ref>pmid 17207484</ref> <ref>pmid 20689707</ref> <ref>pmid 17207484</ref> | ||
