Linked Life Data

11425307

Source:http://linkedlifedata.com/resource/pubmed/id/11425307

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
26
pubmed:dateCreated
2001-6-26
pubmed:abstractText
Nitric oxide (NO) is involved in the regulation of respiration by acting as a competitive ligand for molecular oxygen at the binuclear active site of cytochrome c oxidase. The dynamics of NO in and near this site are not well understood. We performed flash photolysis studies of NO from heme a3 in cytochrome c oxidase from Paracoccus denitrificans, using femtosecond transient absorption spectroscopy. The formation of the product state--the unliganded heme a3 ground state--occurs in a similar stepwise manner (period approximately 700 fs) as previously observed for carbon monoxide photolysis from this enzyme and interpreted in terms of ballistic ligand motions in the active site on the subpicosecond time scale [Liebl, U., Lipowski, G., Négrerie, M., Lambry, J.-C., Martin, J.-L., and Vos, M. H. (1999) Nature 401, 181-184]. A fraction (approximately 35% at very low NO concentrations) of the dissociated NO recombines with heme a3 in 200-300 ps. The presence of this recombination phase indicates that a transient bond to the second ligand-binding site, a copper atom (CuB), has a short lifetime or may not be formed. Increasing the NO concentration increases the recombination yield on the hundreds of picoseconds time scale. This effect, unprecedented for heme proteins, implies that, apart from the one NO molecule bound to heme a3, a second NO molecule can be accommodated in the active site, even at relatively low (submicromolar) concentrations. Models for NO accommodation in the active site, based on molecular dynamics energy minimizations are presented. Pathways for NO motion and their relevance for the regulation of respiration are discussed.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
3
pubmed:volume
40
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
7806-11
pubmed:dateRevised
2003-11-14
pubmed:meshHeading
pubmed:year
2001
pubmed:articleTitle
Dynamics of nitric oxide in the active site of reduced cytochrome c oxidase aa3.
pubmed:affiliation
Laboratory for Optical Biosciences, INSERM U451, CNRS URA 7645, Ecole Polytechnique-ENSTA, 91128 Palaiseau Cedex, France. Marten.Vos@polytechnique.fr
pubmed:publicationType
Journal Article