Desulfovibrio gigas cytochrome

In the sulfate-reducing bacteria there is another cytochrome which resembles cytochrome c3 in the spectral properties and redox potential but differs from this cytochrome in molecular mass this is cytochrome c3 (26 kDa) which has eight heme C molecules in the molecule. The cytochrome molecule is composed of two polypeptides of 13 kDa (Loufti et al., 1989). On the basis of the amino acid sequence, however, the 13 kDa polypeptide differs from cytochrome c3 (Guer-lesquin et al., 1982 LeGall and Peck, 1987 Loufti et al., 1989). Desulfovibrio gigas cytochrome c3 (26 kDa) molecule is composed of two 13 kDa molecules bound to each other by an S-S bond (Bruschi et al., 1996). It is claimed that cytochrome c3 (26 kDa) is very effective as the electron donor for thiosulfate reductase (Hat-chikian et al., 1972). 

Frazao, C., Sieker, L., Sheldrick, G. M., Famzin, V.,LeGall,J. and Carrondo, M. A. (1999). Ab initio structure solution of a dimeric cytochrome c3 from Desulfovibrio gigas containing disulfide bridges. /. Biol. Inorg. Chem. 4, 162-165. 

NiFe Desulfovibrio gigas Periplasm, soluble H2 consumption/ production 61 + 28 Ni/Fe + [3Fe-4S] + 2[4Fe-4S] Cytochrome c3... 

C.acidi-urici ferredoxin and several other ferredoxins. NMR has also been used to characterize three forms of ferredoxin from the sulphate reducing bacteria of Desulfovibrio gigas. (740) One of these ferredoxins is tetrameric and its interaction with cytochrome C3 has been followed. (741)... 

Mafias PM, Morals J, Coelho R, Carrondo MA, Wilson K, Dauter Z, et al. Cytochrome C3 from Desulfovibrio gigas crystal structure at 1.8 A resolution and evidence for a specific calcium binding site. Protein Sci. 1996 5 1342-1354. 

Ambler RP, Bruschi M, KeGall J (1969) The structure of cytochrome c3 from Desulfovibrio gigas (NCIB 9332). FEBS Lett 5 115-117... 

Bruschi M, Leroy G, Bonicel J, Campese D, Dolla A (1996) The cytochrome c3 family amino acid sequence of dimeric octahaem cytochrome c3 (Mr 26000) isolated from Desulfovibrio gigas. Biochem J 320 933-938... 

Chan CW, Suzuki I (1994) Thiosulfate oxidation by sulfur-grown Thiobacillus thiooxidans cells, cell-free extracts, and thiosulfate-oxidizing enzyme. Can J Microbiol 40 816-822 Chan L, Pereira MM, Xavier AV, LeGall J (1994) Isolation and characterization of a high molecular weight cytochrome from the sulfate reducing bacterium Desulfovibrio gigas. FEBS Lett 347 295-299... 

A cytochrome containing eight hemes has been isolated from D. gigas [67], Desulfomicrobium baculatum Norway 4 [68] and Desulfovibrio africanus [69]. It has been named as the cytochrome c3 (Mr 26,000) because of its molecular mass of 26 kDa, but was previously known as cytochrome cc3. It was shown to be composed of two identical 4-heme subunits of 13,500 Da, both in Dsm. baculatum Norway 4 [70], and in D. gigas [71]. In this last case the two subunits are linked by two disulfide bridges. 

If all the flavodoxins isolated from several species of Desulfovibrio are acidic, (low isoelectric points), the tetrahemic cytochromes cs are characterised by a wide range of pi values. The isoelectric points of the three cytochromes C3 studied in this work, D. vulgaris Miyazaki F, D, desulfuricans ATCC 27774 and D. gigas, are 9.5, 7.0 and 3.5, respectively. It is therefor interesting to compare the distribution of the electrostatic potential, over the surface of these proteins. The observed asymmetry of the surface charges was already emphasised in the case of D. vulgaris cytochrome C3 [Stewart et al., 1988] and was used as a basis to predict which of the four hemes should preferentially interact with D. vulgaris flavodoxin. 

---