Linked Life Data

12594218

Source:http://linkedlifedata.com/resource/pubmed/id/12594218

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
17
pubmed:dateCreated
2003-4-21
pubmed:abstractText
We report the first study of O(2) migration in the putative O(2) channel of cytochrome ba(3) and its effect to the properties of the binuclear heme a(3)-Cu(B) center of cytochrome ba(3) from Thermus thermophilus. The Fourier transform infrared spectra of the ba(3)-CO complex demonstrate that in the presence of 60-80 micro m O(2), the nu(C-O) of Cu(B)1+-C-O at 2053 cm(-1) (complex A) shifts to 2045 cm(-1) and remains unchanged in H(2)O/D(2)O exchanges and in the pH 6.5-9.0 range. The frequencies but not the intensities of the C-O stretching modes of heme a(3)-CO (complex B), however, remain unchanged. The change in the nu(C-O) of complex A results in an increase of k(-2), and thus in a higher affinity of Cu(B) for exogenous ligands. The time-resolved step-scan Fourier transform infrared difference spectra indicate that the rate of decay of the transient Cu(B)1+-CO complex at pH 6.5 is 30.4 s(-1) and 28.3 s(-1) in the presence of O(2). Similarly, the rebinding to heme a(3) is slightly affected and occurs with k(2) = 26.3 s(-1) and 24.6 s(-1) in the presence of O(2). These results provide solid evidence that in cytochrome ba(3), the ligand delivery channel is located at the Cu(B) site, which is the ligand entry to the heme a(3) pocket. We suggest that the properties of the O(2) channel are not limited to facilitating ligand diffusion to the active site but are extended in controlling the dynamics and reactivity of the reactions of ba(3) with O(2) and NO.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
25
pubmed:volume
278
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
14893-6
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2003
pubmed:articleTitle
Oxygen-linked equilibrium CuB-CO species in cytochrome ba3 oxidase from thermus thermophilus. Implications for an oxygen channel ar the CuB site.
pubmed:affiliation
University of Crete, Department of Chemistry, 71409 Heraklion, Crete, Greece.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't