Linked Life Data

15907932

Source:http://linkedlifedata.com/resource/pubmed/id/15907932

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
2005-6-1
pubmed:abstractText
Two-dimensional crystals of dimeric photosynthetic reaction centre-LH1-PufX complexes have been analysed by cryoelectron microscopy. The 8.5A resolution projection map extends previous analyses of complexes within native membranes to reveal the alpha-helical structure of two reaction centres and 28 LH1 alphabeta subunits within the dimer. For the first time, we have achieved sufficient resolution to suggest a possible location for the PufX transmembrane helix, the orientation of the RC and the arrangement of helices within the surrounding LH1 complex. Whereas low-resolution projections have shown an apparent break in the LH1, our current map reveals a diffuse density within this region, possibly reflecting high mobility. Within this region the separation between beta14 of one monomer and beta2 of the other monomer is approximately 6A larger than the average beta-beta spacing within LH1; we propose that this is sufficient for exchange of quinol at the RC Q(B) site. We have determined the position and orientation of the RC within the dimer, which places its Q(B) site adjacent to the putative PufX, with access to the point in LH1 that appears most easily breached. PufX appears to occupy a strategic position between the mobile alphabeta14 subunit and the Q(B) site, suggesting how the structure, possibly coupled with a flexible ring, plays a role in optimizing quinone exchange during photosynthesis.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0022-2836
pubmed:author
pubmed:issnType
Print
pubmed:day
24
pubmed:volume
349
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
948-60
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2005
pubmed:articleTitle
The 8.5A projection structure of the core RC-LH1-PufX dimer of Rhodobacter sphaeroides.
pubmed:affiliation
Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield S10 2TN, UK.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't