2GMR

Photosynthetic reaction center mutant from Rhodobacter sphaeroides with Asp L210 replaced with Asn

Summary for 2GMR

• Entry DOI: 10.2210/pdb2gmr/pdb
• Descriptor: Photosynthetic Reaction center protein L chain, Photosynthetic Reaction center protein M chain, Photosynthetic reaction center protein H chain, ... (10 entities in total)
• Functional Keywords: photosynthetic reaction center, integral membrane protein, electron transport, proton transfer, l210dn, mutant, photosynthesis
• Biological source: Rhodobacter sphaeroides; More
• Cellular location: Cellular chromatophore membrane ; Multi-pass membrane protein : Q3J1A5 P0C0Y9; Cellular chromatophore membrane; Single-pass membrane protein: P0C0Y7
• Total number of polymer chains: 3
• Total formula weight: 102529.85

Authors

Stachnik, J.M.,Hermes, S.,Gerwert, K.,Hofmann, E. (deposition date: 2006-04-07, release date: 2006-11-21, Last modification date: 2023-08-30)

Primary citation

Hermes, S.,Stachnik, J.M.,Onidas, D.,Remy, A.,Hofmann, E.,Gerwert, K.
Proton uptake in the reaction center mutant L210DN from Rhodobacter sphaeroides via protonated water molecules.
Biochemistry, 45:13741-13749, 2006

PubMed Abstract: The reaction center (RC) of Rhodobacter sphaeroides uses light energy to reduce and protonate a quinone molecule, QB (the secondary quinone electron acceptor), to form quinol, QBH2. Asp210 in the L-subunit has been shown to be a catalytic residue in this process. Mutation of Asp210 to Asn leads to a deceleration of reoxidation of QA- in the QA-QB --> QAQB- transition. Here we determined the structure of the Asp210 to Asn mutant to 2.5 A and show that there are no major structural differences as compared to the wild-type protein. We found QB in the distal position and a chain of water molecules between Asn210 and QB. Using time-resolved Fourier transform infrared (trFTIR) spectroscopy, we characterized the molecular reaction mechanism of this mutant. We found that QB- formation precedes QA- oxidation even more pronounced than in the wild-type reaction center. Continuum absorbance changes indicate deprotonation of a protonated water cluster, most likely of the water chain between Asn210 and QB. A detailed analysis of wild-type structures revealed a highly conserved water chain between Asp210 or Glu210 and QB in Rb. sphaeroides and Rhodopseudomonas viridis, respectively.

PubMed: 17105193
DOI: 10.1021/bi060742q

Experimental method

X-RAY DIFFRACTION (2.5 Å)