8VTK
Crystal structure of R.sphaeroides Photosynthetic Reaction Center variant Y(M210)2-chlorophenylalanine
Summary for 8VTK
| Entry DOI | 10.2210/pdb8vtk/pdb |
| Descriptor | Reaction center protein H chain, SPHEROIDENE, CARDIOLIPIN, ... (12 entities in total) |
| Functional Keywords | photosynthesis, membrane protein, electron transfer |
| Biological source | Cereibacter sphaeroides More |
| Total number of polymer chains | 3 |
| Total formula weight | 99972.32 |
| Authors | Tran, K.,Mathews, I.,Boxer, S.G. (deposition date: 2024-01-26, release date: 2024-03-13, Last modification date: 2025-09-24) |
| Primary citation | Tran, K.N.,Faries, K.M.,Magdaong, N.C.M.,Mathews, I.I.,Weaver, J.B.,Kirsh, J.M.,Holten, D.,Kirmaier, C.,Boxer, S.G. Application of Amber Suppression To Study the Role of Tyr M210 in Electron Transfer in Rhodobacter sphaeroides Photosynthetic Reaction Centers. J.Phys.Chem.B, 129:3317-3333, 2025 Cited by PubMed Abstract: The initial light-induced electron transfer (ET) steps in the bacterial photosynthetic reaction center (RC) have been extensively studied and provide a paradigm for connecting structure and function. Although RCs have local pseudo- symmetry, ET only occurs along the A branch of chromophores. Tyrosine M210 is a key symmetry-breaking residue adjacent to bacteriochlorophyll B that bridges the primary electron donor P and the bacteriopheophytin acceptor H. We used amber suppression to incorporate phenylalanine variants with different electron-withdrawing/-donating capabilities at the position M210. X-ray data generally reveal no appreciable structural changes due to the mutations. P* decay and PH formation are multiexponential (∼2 to 9, ∼10 to 60, and ∼100 to 300 ps) and temperature dependent. The 1020 nm transient-absorption band of PB is barely resolved for a few variants at 295 K and for none at 77 K. The results indicate a change from two-step ET for wild-type RCs to the dominance of one-step superexchange ET for the mutants. Resonance Stark spectroscopy reveals that the free energy of PB changes by -57 to +66 meV among the phenylalanine variants. Because PB apparently lies above P* in all phenylalanine variants, the perturbations primarily affect the energy denominator for superexchange mixing. The findings deepen insight into primary ET in the bacterial RC. PubMed: 40134359DOI: 10.1021/acs.jpcb.5c00082 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (3.07 Å) |
Structure validation
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