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rdf:type |
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lifeskim:mentions |
umls-concept:C0017797,
umls-concept:C0033727,
umls-concept:C0053241,
umls-concept:C0061472,
umls-concept:C0175668,
umls-concept:C0243127,
umls-concept:C0443331,
umls-concept:C0521009,
umls-concept:C0559956,
umls-concept:C1547239,
umls-concept:C1704259,
umls-concept:C1705987,
umls-concept:C1711351,
umls-concept:C2755839
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pubmed:issue |
17
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pubmed:dateCreated |
1989-10-6
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pubmed:abstractText |
The mechanism of proton transfer in the reaction centers (RCs) from Rhodobacter sphaeroides was investigated by site-directed mutagenesis. Replacement of Glu-212 of the L subunit, a protonatable residue located near the secondary acceptor (QB) binding site, by glutamine reduced the in vitro electron turnover from cytochrome c to 2,3-dimethoxy-5-methylbenzoquinone (UQ0) by a factor of 25. The electron transfer rate to QB remained essentially unimpaired. Consequently, it is postulated that the reduced turnover in the mutant is due to a reduced rate of proton transfer to QB2-. The lack of pH dependence of the forward electron transfer rate DQA-QB----DQAQB- and the back reaction rate D+QAQB- ----DQAQB (where D = primary donor and QA = primary acceptor) in the mutant RC indicate that the observed pH dependence in the native RC is due to Glu-212, which has an anomalously high pKa value of 9.5 +/- 0.3. These results support the involvement of Glu-212 as a proton donor to reduced QB.
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pubmed:grant |
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pubmed:commentsCorrections |
http://linkedlifedata.com/resource/pubmed/commentcorrection/2570421-16453868,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2570421-2825125,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2570421-2836382,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2570421-2876725,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2570421-2896197,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2570421-2987994,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2570421-3016464,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2570421-3054889,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2570421-3288985,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2570421-3323803,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2570421-3864717,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2570421-407213,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2570421-41574,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2570421-6095283,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2570421-6295879,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2570421-6306243,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2570421-6331502
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pubmed:language |
eng
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pubmed:journal |
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pubmed:citationSubset |
IM
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pubmed:chemical |
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pubmed:status |
MEDLINE
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pubmed:month |
Sep
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pubmed:issn |
0027-8424
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pubmed:author |
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pubmed:issnType |
Print
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pubmed:volume |
86
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
6602-6
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pubmed:dateRevised |
2010-9-9
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pubmed:meshHeading |
pubmed-meshheading:2570421-Bacterial Proteins,
pubmed-meshheading:2570421-Chromosome Deletion,
pubmed-meshheading:2570421-Cytochrome c Group,
pubmed-meshheading:2570421-Electron Transport,
pubmed-meshheading:2570421-Genes,
pubmed-meshheading:2570421-Genes, Bacterial,
pubmed-meshheading:2570421-Glutamates,
pubmed-meshheading:2570421-Glutamic Acid,
pubmed-meshheading:2570421-Glutamine,
pubmed-meshheading:2570421-Kinetics,
pubmed-meshheading:2570421-Light,
pubmed-meshheading:2570421-Models, Molecular,
pubmed-meshheading:2570421-Mutation,
pubmed-meshheading:2570421-Photosynthetic Reaction Center Complex Proteins,
pubmed-meshheading:2570421-Protein Conformation,
pubmed-meshheading:2570421-Quinones,
pubmed-meshheading:2570421-Restriction Mapping,
pubmed-meshheading:2570421-Rhodobacter sphaeroides
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pubmed:year |
1989
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pubmed:articleTitle |
Pathway of proton transfer in bacterial reaction centers: replacement of glutamic acid 212 in the L subunit by glutamine inhibits quinone (secondary acceptor) turnover.
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pubmed:affiliation |
Department of Physics, University of California, San Diego, La Jolla 92093.
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pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.,
Research Support, U.S. Gov't, Non-P.H.S.
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