Recent advances in the characterization of the hexadecahemic cytochrome c from Desulfovibrio

The bacterial metallome: composition and stability with specific reference to the anaerobic bacterium Desulfovibrio desulfuricans

“…With hydrogenases and ferredoxin, metal reduction may be associated with iron-sulfur centers because they have a For cytochromes it appears that the key characteristics for metal reduction would include a heme with low (-100 mV to -400 mV), a bis-histidinyl coordination of heme, and a slightly positive charge on the protein around the heme to facilitate interfacing of the heme and redox metals. Studies on the cytochrome c 3 family described by Bruschi (1994) and Florens and Bruschi (1994) have demonstrated that the metal reduction activity of these multihemic proteins is linked to the low redox potential of the heme moieties of the cytochrome.…”

The bacterial metallome: composition and stability with specific reference to the anaerobic bacterium Desulfovibrio desulfuricans

“…With hydrogenases and ferredoxin, metal reduction may be associated with iron-sulfur centers because they have a For cytochromes it appears that the key characteristics for metal reduction would include a heme with low (-100 mV to -400 mV), a bis-histidinyl coordination of heme, and a slightly positive charge on the protein around the heme to facilitate interfacing of the heme and redox metals. Studies on the cytochrome c 3 family described by Bruschi (1994) and Florens and Bruschi (1994) have demonstrated that the metal reduction activity of these multihemic proteins is linked to the low redox potential of the heme moieties of the cytochrome.…”

Nature's nitrite-to-ammonia expressway, with no stop at dinitrogen

“…In aerobic and anaerobic microbes, especially those of the biological nitrogen and sulfur cycles, there are many c -type cytochromes with multiple heme centers per polypeptide chain [ 2 , 3 , 5 , 23 , 25 – 32 , 35 , 55 , 98 , 103 , 114 – 122 ]. Early examples include the octaheme hydroxylamine oxidoreductase (HAO) and related proteins [ 123 – 129 ], the tetraheme NapC/NirT/TorC family [ 130 ], the 16-heme-containing protein Hmc (high molecular mass cytochrome c ) from sulfate-reducing bacteria [ 131 , 132 ], the octaheme tetrathionate reductase from Shewanella oneidensis [ 133 , 134 ], the tetraheme cytochrome c 3 described in the previous section, and the pentaheme cytochrome c nitrite reductase, the central enzyme of this review. These multiheme proteins form structurally related families, in which the positions of the heme can often be overlaid, even when there is little sequence conservation between members of the family, e.g., pentaheme nitrite reductase NrfA, octaheme HAO, and flavocytochrome fumarate reductase [ 22 , 133 – 135 ].…”

C-type cytochromes: diverse structures and biogenesis systems pose evolutionary problems

“…In the bacterial world, especially as part of the biological nitrogen and sulphur cycles, there are many c-type cytochromes with multiple haems per polypeptide chain. Examples include the octahaem hydroxylamine oxidoreductase (Igarashi et al 1997), the tetrahaem NapC/NirT/TorC family (Roldan et al 1998), the 65 kDa 16-haem-containing protein Hmc (high molecular mass cytochrome c) from sulphate-reducing bacteria (Florens & Bruschi 1994), and cytochrome c 3 which is, remarkably, a tetrahaem protein of only ca. 16 kDa molecular mass (Higuchi et al 1984).…”

The bacterial metallome: composition and stability with specific reference to the anaerobic bacterium Desulfovibrio desulfuricans

“…With hydrogenases and ferredoxin, metal reduction may be associated with iron-sulfur centers because they have a For cytochromes it appears that the key characteristics for metal reduction would include a heme with low (-100 mV to -400 mV), a bis-histidinyl coordination of heme, and a slightly positive charge on the protein around the heme to facilitate interfacing of the heme and redox metals. Studies on the cytochrome c 3 family described by Bruschi (1994) and Florens and Bruschi (1994) have demonstrated that the metal reduction activity of these multihemic proteins is linked to the low redox potential of the heme moieties of the cytochrome.…”

Nature's nitrite-to-ammonia expressway, with no stop at dinitrogen

“…In aerobic and anaerobic microbes, especially those of the biological nitrogen and sulfur cycles, there are many c -type cytochromes with multiple heme centers per polypeptide chain [ 2 , 3 , 5 , 23 , 25 – 32 , 35 , 55 , 98 , 103 , 114 – 122 ]. Early examples include the octaheme hydroxylamine oxidoreductase (HAO) and related proteins [ 123 – 129 ], the tetraheme NapC/NirT/TorC family [ 130 ], the 16-heme-containing protein Hmc (high molecular mass cytochrome c ) from sulfate-reducing bacteria [ 131 , 132 ], the octaheme tetrathionate reductase from Shewanella oneidensis [ 133 , 134 ], the tetraheme cytochrome c 3 described in the previous section, and the pentaheme cytochrome c nitrite reductase, the central enzyme of this review. These multiheme proteins form structurally related families, in which the positions of the heme can often be overlaid, even when there is little sequence conservation between members of the family, e.g., pentaheme nitrite reductase NrfA, octaheme HAO, and flavocytochrome fumarate reductase [ 22 , 133 – 135 ].…”

C-type cytochromes: diverse structures and biogenesis systems pose evolutionary problems

“…In the bacterial world, especially as part of the biological nitrogen and sulphur cycles, there are many c-type cytochromes with multiple haems per polypeptide chain. Examples include the octahaem hydroxylamine oxidoreductase (Igarashi et al 1997), the tetrahaem NapC/NirT/TorC family (Roldan et al 1998), the 65 kDa 16-haem-containing protein Hmc (high molecular mass cytochrome c) from sulphate-reducing bacteria (Florens & Bruschi 1994), and cytochrome c 3 which is, remarkably, a tetrahaem protein of only ca. 16 kDa molecular mass (Higuchi et al 1984).…”

The bacterial metallome: composition and stability with specific reference to the anaerobic bacterium Desulfovibrio desulfuricans

“…With hydrogenases and ferredoxin, metal reduction may be associated with iron-sulfur centers because they have a For cytochromes it appears that the key characteristics for metal reduction would include a heme with low (-100 mV to -400 mV), a bis-histidinyl coordination of heme, and a slightly positive charge on the protein around the heme to facilitate interfacing of the heme and redox metals. Studies on the cytochrome c 3 family described by Bruschi (1994) and Florens and Bruschi (1994) have demonstrated that the metal reduction activity of these multihemic proteins is linked to the low redox potential of the heme moieties of the cytochrome.…”

Nature's nitrite-to-ammonia expressway, with no stop at dinitrogen

“…In aerobic and anaerobic microbes, especially those of the biological nitrogen and sulfur cycles, there are many c -type cytochromes with multiple heme centers per polypeptide chain [ 2 , 3 , 5 , 23 , 25 – 32 , 35 , 55 , 98 , 103 , 114 – 122 ]. Early examples include the octaheme hydroxylamine oxidoreductase (HAO) and related proteins [ 123 – 129 ], the tetraheme NapC/NirT/TorC family [ 130 ], the 16-heme-containing protein Hmc (high molecular mass cytochrome c ) from sulfate-reducing bacteria [ 131 , 132 ], the octaheme tetrathionate reductase from Shewanella oneidensis [ 133 , 134 ], the tetraheme cytochrome c 3 described in the previous section, and the pentaheme cytochrome c nitrite reductase, the central enzyme of this review. These multiheme proteins form structurally related families, in which the positions of the heme can often be overlaid, even when there is little sequence conservation between members of the family, e.g., pentaheme nitrite reductase NrfA, octaheme HAO, and flavocytochrome fumarate reductase [ 22 , 133 – 135 ].…”

C-type cytochromes: diverse structures and biogenesis systems pose evolutionary problems

“…In the bacterial world, especially as part of the biological nitrogen and sulphur cycles, there are many c-type cytochromes with multiple haems per polypeptide chain. Examples include the octahaem hydroxylamine oxidoreductase (Igarashi et al 1997), the tetrahaem NapC/NirT/TorC family (Roldan et al 1998), the 65 kDa 16-haem-containing protein Hmc (high molecular mass cytochrome c) from sulphate-reducing bacteria (Florens & Bruschi 1994), and cytochrome c 3 which is, remarkably, a tetrahaem protein of only ca. 16 kDa molecular mass (Higuchi et al 1984).…”