| Structural highlights
4fe1 is a 10 chain structure with sequence from Thermosynechococcus vestitus BP-1. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
| | Method: | X-ray diffraction, Resolution 4.9228Å |
| Ligands: | , , , , , |
| Resources: | FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT |
Function
PSAA_THEVB PsaA and PsaB bind P700, the primary electron donor of photosystem I (PSI), as well as the electron acceptors A0, A1 and FX. PSI is a plastocyanin/cytochrome c6-ferredoxin oxidoreductase, converting photonic excitation into a charge separation, which transfers an electron from the donor P700 chlorophyll pair to the spectroscopically characterized acceptors A0, A1, FX, FA and FB in turn. Oxidized P700 is reduced on the lumenal side of the thylakoid membrane by plastocyanin or cytochrome c6.[1] [2] [3] [4]
Publication Abstract from PubMed
In X-ray crystallography, molecular replacement and subsequent refinement is challenging at low resolution. We compared refinement methods using synchrotron diffraction data of photosystem I at 7.4 A resolution, starting from different initial models with increasing deviations from the known high-resolution structure. Standard refinement spoiled the initial models, moving them further away from the true structure and leading to high R(free)-values. In contrast, DEN refinement improved even the most distant starting model as judged by R(free), atomic root-mean-square differences to the true structure, significance of features not included in the initial model, and connectivity of electron density. The best protocol was DEN refinement with initial segmented rigid-body refinement. For the most distant initial model, the fraction of atoms within 2 A of the true structure improved from 24% to 60%. We also found a significant correlation between R(free) values and the accuracy of the model, suggesting that R(free) is useful even at low resolution.
Improving the accuracy of macromolecular structure refinement at 7 A resolution.,Brunger AT, Adams PD, Fromme P, Fromme R, Levitt M, Schroder GF Structure. 2012 Jun 6;20(6):957-66. PMID:22681901[5]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Klukas O, Schubert WD, Jordan P, Krauss N, Fromme P, Witt HT, Saenger W. Photosystem I, an improved model of the stromal subunits PsaC, PsaD, and PsaE. J Biol Chem. 1999 Mar 12;274(11):7351-60. PMID:10066799
- ↑ Klukas O, Schubert WD, Jordan P, Krau N, Fromme P, Witt HT, Saenger W. Localization of two phylloquinones, QK and QK', in an improved electron density map of photosystem I at 4-A resolution. J Biol Chem. 1999 Mar 12;274(11):7361-7. PMID:10066800
- ↑ Jordan P, Fromme P, Witt HT, Klukas O, Saenger W, Krauss N. Three-dimensional structure of cyanobacterial photosystem I at 2.5 A resolution. Nature. 2001 Jun 21;411(6840):909-17. PMID:11418848 doi:10.1038/35082000
- ↑ Krauss N, Schubert WD, Klukas O, Fromme P, Witt HT, Saenger W. Photosystem I at 4 A resolution represents the first structural model of a joint photosynthetic reaction centre and core antenna system. Nat Struct Biol. 1996 Nov;3(11):965-73. PMID:8901876
- ↑ Brunger AT, Adams PD, Fromme P, Fromme R, Levitt M, Schroder GF. Improving the accuracy of macromolecular structure refinement at 7 A resolution. Structure. 2012 Jun 6;20(6):957-66. PMID:22681901 doi:10.1016/j.str.2012.04.020
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