Amino acid sequence, crystallization and structure determination of reduced and oxidized cytochrome c6 from the green alga Scenedesmus obliquus

Schnackenberg, Jörg; Than, Manuel E.; Mann, Karlheinz; Wiegand, Georg; Huber, Robert; Reuter, W

doi:10.1006/jmbi.1999.2944

Cited by 42 publications

(60 citation statements)

References 46 publications

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“…3) and conserved among c-type cytochromes, is detected in the same position in both redox states. Recently, structural determinations of the cytochrome c 6 from Scenedesmus obliquus in both redox states revealed no redox-dependent movement of the internal water molecule (Schnackenberg et al 1999). As Rps.…”

Section: Discussionmentioning

confidence: 99%

Cleavage of the iron-methionine bond in c-type cytochromes: Crystal structure of oxidized and reduced cytochrome c2 from Rhodopseudomonas palustris and its ammonia complex

et al. 2002

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The three-dimensional structures of the native cytochrome c 2 from Rhodopseudomonas palustris and of its ammonia complex have been obtained at pH 4.4 and pH 8.5, respectively. The structure of the native form has been refined in the oxidized state at 1.70 Å and in the reduced state at 1.95 Å resolution. These are the first high-resolution crystal structures in both oxidation states of a cytochrome c 2 with relatively high redox potential (+350 mV). The differences between the two oxidation states of the native form, including the position of internal water molecules, are small. The unusual six-residue insertion Gly82-Ala87, which precedes the heme binding Met93, forms an isolated 3 10 -helix secondary structural element not previously observed in other c-type cytochromes. Furthermore, this cytochrome shows an external methionine residue involved in a strained folding near the exposed edge of the heme. The structural comparison of the present cytochrome c 2 with other c-type cytochromes has revealed that the presence of such a residue, with torsion angles and of approximately −140 and −130°, respectively, is a typical feature of this family of proteins. The refined crystal structure of the ammonia complex, obtained at 1.15 Å resolution, shows that the sulphur atom of the Met93 axial ligand does not coordinate the heme iron atom, but is replaced by an exogenous ammonia molecule. This is the only example so far reported of an X-ray structure with the heme iron coordinated by an ammonia molecule. The detachment of Met93 is accompanied by a very localized change in backbone conformation, involving mainly the residues Lys92, Met93, and Thr94. Previous studies under typical denaturing conditions, including high-pH values and the presence of exogenous ligands, have shown that the detachment of the Met axial ligand is a basic step in the folding/unfolding process of c-type cytochromes. The ammonia adduct represents a structural model for this important step of the unfolding pathway. Factors proposed to be important for the methionine dissociation are the strength of the H-bond between the Met93 and Tyr66 residues that stabilizes the native form, and the presence in this bacterial cytochrome c 2 of the rare six-residue insertion in the helix 3 10 conformation that increases Met loop flexibility.

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Section: Discussionmentioning

confidence: 99%

Cleavage of the iron-methionine bond in c-type cytochromes: Crystal structure of oxidized and reduced cytochrome c2 from Rhodopseudomonas palustris and its ammonia complex

et al. 2002

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“…These water molecules are located at close positions to the water binding site observed in class I cytochromes, such as yeast mitochondrial cytochrome c, 29,30 cytochrome c 2 from the purple bacterium Blastochloris (formerly Rhodopseudomonas) viridis, 31 and cytochrome c 6 from the green alga Scenedesmus obliquus. 32 In chain A of C-cyt c z , a hydrogen bond between the water (Wat804) and Tyr169 has similarities to the hydrogen bond between Wat166 and Tyr67 in yeast mitochondrial cytochrome c (Fig. 6b).…”

Section: Heme Environmentmentioning

confidence: 94%

Crystal Structure of the Electron Carrier Domain of the Reaction Center Cytochrome cz Subunit from Green Photosynthetic Bacterium Chlorobium tepidum

Hirano

Higuchi

Azai

et al. 2010

Journal of Molecular Biology

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In green sulfur photosynthetic bacteria, the cytochrome c(z) (cyt c(z)) subunit in the reaction center complex mediates electron transfer mainly from menaquinol/cytochrome c oxidoreductase to the special pair (P840) of the reaction center. The cyt c(z) subunit consists of an N-terminal transmembrane domain and a C-terminal soluble domain that binds a single heme group. The periplasmic soluble domain has been proposed to be highly mobile and to fluctuate between oxidoreductase and P840 during photosynthetic electron transfer. We have determined the crystal structure of the oxidized form of the C-terminal functional domain of the cyt c(z) subunit (C-cyt c(z)) from thermophilic green sulfur bacterium Chlorobium tepidum at 1.3-A resolution. The overall fold of C-cyt c(z) consists of four alpha-helices and is similar to that of class I cytochrome c proteins despite the low similarity in their amino acid sequences. The N-terminal structure of C-cyt c(z) supports the swinging mechanism previously proposed in relation with electron transfer, and the surface properties provide useful information on possible interaction sites with its electron transfer partners. Several characteristic features are observed for the heme environment: These include orientation of the axial ligands with respect to the heme plane, surface-exposed area of the heme, positions of water molecules, and hydrogen-bond network involving heme propionate groups. These structural features are essential for elucidating the mechanism for regulating the redox state of cyt c(z).

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“…3,4 The structures of seven cytochromes c 6 have been previously determined. [4][5][6][7][8][9][10] Further, a c 6 -like cytochrome (PetJ2) of unknown function was recently identified in Synechoccus sp. PCC 7002 with a reduction potential of 1148 mV and high pI.…”

Section: Introductionmentioning

confidence: 99%

Outer membrane cytochrome c, OmcF, from Geobacter sulfurreducens: High structural similarity to an algal cytochrome c₆

et al. 2008

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Amino acid sequence, crystallization and structure determination of reduced and oxidized cytochrome c6 from the green alga Scenedesmus obliquus

Cited by 42 publications

References 46 publications

Cleavage of the iron-methionine bond in c-type cytochromes: Crystal structure of oxidized and reduced cytochrome c2 from Rhodopseudomonas palustris and its ammonia complex

Cleavage of the iron-methionine bond in c-type cytochromes: Crystal structure of oxidized and reduced cytochrome c2 from Rhodopseudomonas palustris and its ammonia complex

Crystal Structure of the Electron Carrier Domain of the Reaction Center Cytochrome cz Subunit from Green Photosynthetic Bacterium Chlorobium tepidum

Outer membrane cytochrome c, OmcF, from Geobacter sulfurreducens: High structural similarity to an algal cytochrome c₆

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Amino acid sequence, crystallization and structure determination of reduced and oxidized cytochrome c6 from the green alga Scenedesmus obliquus

Cited by 42 publications

References 46 publications

Cleavage of the iron-methionine bond in c-type cytochromes: Crystal structure of oxidized and reduced cytochrome c2 from Rhodopseudomonas palustris and its ammonia complex

Cleavage of the iron-methionine bond in c-type cytochromes: Crystal structure of oxidized and reduced cytochrome c2 from Rhodopseudomonas palustris and its ammonia complex

Crystal Structure of the Electron Carrier Domain of the Reaction Center Cytochrome cz Subunit from Green Photosynthetic Bacterium Chlorobium tepidum

Outer membrane cytochrome c, OmcF, from Geobacter sulfurreducens: High structural similarity to an algal cytochrome c6

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Outer membrane cytochrome c, OmcF, from Geobacter sulfurreducens: High structural similarity to an algal cytochrome c₆