Linked Life Data

15147175

Source:http://linkedlifedata.com/resource/pubmed/id/15147175

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
20
pubmed:dateCreated
2004-5-18
pubmed:abstractText
Structures of the cytochrome b(6)f complex obtained from the thermophilic cyanobacterium Mastigocladus laminosus and the green alga Chlamydomonas reinhardtii, whose appearance in evolution is separated by 10(9) years, are almost identical. Two monomers with a molecular weight of 110,000, containing eight subunits and seven natural prosthetic groups, are separated by a large lipid-containing "quinone exchange cavity". A unique heme, heme x, that is five-coordinated and high-spin, with no strong field ligand, occupies a position close to intramembrane heme b(n). This position is filled by the n-side bound quinone, Q(n), in the cytochrome bc(1) complex of the mitochondrial respiratory chain. The structure and position of heme x suggest that it could function in ferredoxin-dependent cyclic electron transport as well as being an intermediate in a quinone cycle mechanism for electron and proton transfer. The significant differences between the cyanobacterial and algal structures are as follows. (i) On the n-side, a plastoquinone molecule is present in the quinone exchange cavity in the cyanobacterial complex, and a sulfolipid is bound in the algal complex at a position corresponding to a synthetic DOPC lipid molecule in the cyanobacterial complex. (ii) On the p-side, in both complexes a quinone analogue inhibitor, TDS, passes through a portal that separates the large cavity from a niche containing the Fe(2)S(2) cluster. However, in the cyanobacterial complex, TDS is in an orientation that is the opposite of its position in the algal structure and bc(1) complexes, so its headgroup in the M. laminosus structure is 20 A from the Fe(2)S(2) cluster.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
25
pubmed:volume
43
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
5921-9
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
2004
pubmed:articleTitle
Evolution of photosynthesis: time-independent structure of the cytochrome b6f complex.
pubmed:affiliation
Department of Biological Sciences, Lilly Hall of Life Sciences, 915 West State Street, Purdue University, West Lafayette, Indiana 47907-2054, USA. wac@bilbo.bio.purdue.edu
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Review, Research Support, Non-U.S. Gov't