3A9F

Crystal structure of the C-terminal domain of cytochrome cz from Chlorobium tepidum

Summary for 3A9F

• Entry DOI: 10.2210/pdb3a9f/pdb
• Descriptor: Cytochrome c, HEME C, SODIUM ION, ... (8 entities in total)
• Functional Keywords: alpha helix, cytochrome, mono heme, electron transport
• Biological source: Chlorobaculum tepidum
• Cellular location: Cell inner membrane ; Multi-pass membrane protein : O07091
• Total number of polymer chains: 2
• Total formula weight: 22310.21

Authors

Hirano, Y.,Higuchi, M.,Azai, C.,Oh-oka, H.,Miki, K.,Wang, Z.-Y. (deposition date: 2009-10-25, release date: 2010-03-02, Last modification date: 2024-03-13)

Primary citation

Hirano, Y.,Higuchi, M.,Azai, C.,Oh-Oka, H.,Miki, K.,Wang, Z.-Y.
Crystal structure of the electron carrier domain of the reaction center cytochrome c(z) subunit from green photosynthetic bacterium Chlorobium tepidum
J.Mol.Biol., 397:1175-1187, 2010

PubMed Abstract: 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).

PubMed: 20156447
DOI: 10.1016/j.jmb.2010.02.011

Experimental method

X-RAY DIFFRACTION (1.3 Å)