1hcz
From Proteopedia
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'''LUMEN-SIDE DOMAIN OF REDUCED CYTOCHROME F AT-35 DEGREES CELSIUS''' | '''LUMEN-SIDE DOMAIN OF REDUCED CYTOCHROME F AT-35 DEGREES CELSIUS''' | ||
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[[Category: Smith, J L.]] | [[Category: Smith, J L.]] | ||
[[Category: Szczepaniak, A.]] | [[Category: Szczepaniak, A.]] | ||
| - | [[Category: | + | [[Category: Chloroplast transmembrane]] |
| - | [[Category: | + | [[Category: Cytochrome b6f complex]] |
| - | [[Category: | + | [[Category: Electron transport]] |
| - | [[Category: | + | [[Category: Photosynthesis]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 18:42:48 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 15:42, 2 May 2008
LUMEN-SIDE DOMAIN OF REDUCED CYTOCHROME F AT-35 DEGREES CELSIUS
Overview
The crystal structure of the 252-residue lumen-side domain of reduced cytochrome f, a subunit of the proton-pumping integral cytochrome b6f complex of oxygenic photosynthetic membranes, was determined to a resolution of 1.96 A from crystals cooled to -35 degrees. The model was refined to an R-factor of 15.8% with a 0.013-A RMS deviation of bond lengths from ideality. Compared to the structure of cytochrome f at 20 degrees, the structure at -35 degrees has a small change in relative orientation of the two folding domains and significantly lower isotropic temperature factors for protein atoms. The structure revealed an L-shaped array of five buried water molecules that extend in two directions from the N delta 1 of the heme ligand His 25. The longer branch extends 11 A within the large domain, toward Lys 66 in the prominent basic patch at the top of the large domain, which has been implicated in the interaction with the electron acceptor, plastocyanin. The water sites are highly occupied, and their temperature factors are comparable to those of protein atoms. Virtually all residues that form hydrogen bonds with the water chain are invariant among 13 known cytochrome f sequences. The water chain has many features that optimize it as a proton wire, including insulation from the protein medium. It is suggested that this chain may function as the lumen-side exit port for proton translocation by the cytochrome b6f complex.
About this Structure
1HCZ is a Single protein structure of sequence from Brassica rapa. Full crystallographic information is available from OCA.
Reference
The heme redox center of chloroplast cytochrome f is linked to a buried five-water chain., Martinez SE, Huang D, Ponomarev M, Cramer WA, Smith JL, Protein Sci. 1996 Jun;5(6):1081-92. PMID:8762139 Page seeded by OCA on Fri May 2 18:42:48 2008
