Linked Life Data

9545462

Source:http://linkedlifedata.com/resource/pubmed/id/9545462

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
1998-5-29
pubmed:abstractText
The superfamily of quinol and cytochrome c terminal oxidase complexes is related by a homologous subunit containing six positionally conserved histidines that ligate a low-spin heme and a heme-copper dioxygen activating and reduction center. On the basis of the structural similarities of these enzymes, it has been postulated that all members of this superfamily catalyze proton translocation by similar mechanisms and that the CuA center found in most cytochrome c oxidase complexes serves merely as an electron conduit shuttling electrons from ferrocytochrome c into the hydrophobic core of the enzyme. The recent characterization of cytochrome c oxidase complexes and structurally similar cytochrome c:nitric oxide oxidoreductase complexes without CuA centers has strengthened this view. However, recent experimental evidence has shown that there are two ubiquinone(ol) binding sites on the Escherichia coli cytochrome bo3 complex in dynamic equilibrium with the ubiquinone(ol) pool, thereby strengthening the argument for a Q(H2)-loop mechanism of proton translocation [Musser SM et al. (1997) Biochemistry 36:894-902]. In addition, a number of reports suggest that a Q(H2)-loop or another alternate proton translocation mechanism distinct from the mitochondrial aa3-type proton pump functions in Sulfolobus acidocaldarius terminal oxidase complexes. The possibility that a primitive quinol oxidase complex evolved to yield two separate complexes, the cytochrome bc1 and cytochrome c oxidase complexes, is explored here. This idea is the basis for an evolutionary tree constructed using the notion that respiratory complexity and efficiency progressively increased throughout the evolutionary process. The analysis suggests that oxygenic respiration is quite an old process and, in fact, predates nitrogenic respiration as well as reaction-center photosynthesis.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0022-2844
pubmed:author
pubmed:issnType
Print
pubmed:volume
46
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
508-20
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1998
pubmed:articleTitle
Evolution of the cytochrome c oxidase proton pump.
pubmed:affiliation
Division of Chemistry and Chemical Engineering, Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, CA 91125, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Review, Research Support, Non-U.S. Gov't