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| [[Image:2gmr.gif|left|200px]] | | {{Seed}} |
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| {{STRUCTURE_2gmr| PDB=2gmr | SCENE= }} | | {{STRUCTURE_2gmr| PDB=2gmr | SCENE= }} |
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| '''Photosynthetic reaction center mutant from Rhodobacter sphaeroides with Asp L210 replaced with Asn'''
| | ===Photosynthetic reaction center mutant from Rhodobacter sphaeroides with Asp L210 replaced with Asn=== |
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| ==Overview==
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| 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. | | The line below this paragraph, {{ABSTRACT_PUBMED_17105193}}, adds the Publication Abstract to the page |
| | (as it appears on PubMed at http://www.pubmed.gov), where 17105193 is the PubMed ID number. |
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| | {{ABSTRACT_PUBMED_17105193}} |
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| ==About this Structure== | | ==About this Structure== |
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| [[Category: Proton transfer]] | | [[Category: Proton transfer]] |
| [[Category: X-ray crystallography]] | | [[Category: X-ray crystallography]] |
| ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun May 4 05:17:00 2008'' | | |
| | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Tue Jul 29 15:59:20 2008'' |
