Linked Life Data

17570397

Source:http://linkedlifedata.com/resource/pubmed/id/17570397

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2007-7-19
pubmed:databankReference
pubmed:abstractText
The structure of the photosynthetic reaction-center from Rhodobacter sphaeroides has been determined at four different pH values (6.5, 8.0, 9.0, 10.0) in the neutral and in charge separated states. At pH 8.0, in the neutral state, we obtain a resolution of 1.87 A, which is the best ever reported for the bacterial reaction center protein. Our crystallographic data confirm the existence of two different binding positions of the secondary quinone (QB). We observe a new orientation of QB in its distal position, which shows no ring-flip compared to the orientation in the proximal position. Datasets collected for the different pH values show a pH-dependence of the population of the proximal position. The new orientation of QB in the distal position and the pH-dependence could be confirmed by continuum electrostatics calculations. Our calculations are in agreement with the experimentally observed proton uptake upon charge separation. The high resolution of our crystallographic data allows us to identify new water molecules and external residues being involved in two previously described hydrogen bond proton channels. These extended proton-transfer pathways, ending at either of the two oxo-groups of QB in its proximal position, provide additional evidence that ring-flipping is not required for complete protonation of QB upon reduction.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0022-2836
pubmed:author
pubmed:issnType
Print
pubmed:day
10
pubmed:volume
371
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
396-409
pubmed:meshHeading
pubmed:year
2007
pubmed:articleTitle
pH modulates the quinone position in the photosynthetic reaction center from Rhodobacter sphaeroides in the neutral and charge separated states.
pubmed:affiliation
Max Planck Institute of Biophysics, Department of Molecular Membrane Biology, Max-von-Laue Strasse 3, D-60438 Frankfurt/Main, Germany. Juergen.Koepke@mpibp-frankfurt.mpg.de
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't