Linked Life Data

12637529

Source:http://linkedlifedata.com/resource/pubmed/id/12637529

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
21
pubmed:dateCreated
2003-5-19
pubmed:abstractText
We report the first evidence for the formation of the "607- and 580-nm forms" in the cytochrome oxidase aa3/H2O2 reaction without the involvement of tyrosine 280. The pKa of the 607-580-nm transition is 7.5. The 607-nm form is also formed in the mixed valence cytochrome oxidase/O2 reaction in the absence of tyrosine 280. Steady-state resonance Raman characterization of the reaction products of both the wild-type and Y280H cytochrome aa3 from Paracoccus denitrificans indicate the formation of six-coordinate low spin species, and do not support, in contrast to previous reports, the formation of a porphyrin pi-cation radical. We observe three oxygen isotope-sensitive Raman bands in the oxidized wild-type aa3/H2O2 reaction at 804, 790, and 358 cm-1. The former two are assigned to the Fe(IV)[double bond]O stretching mode of the 607- and 580-nm forms, respectively. The 14 cm-1 frequency difference between the oxoferryl species is attributed to variations in the basicity of the proximal to heme a3 His-411, induced by the oxoferryl conformations of the heme a3-CuB pocket during the 607-580-nm transition. We suggest that the 804-790 cm-1 oxoferryl transition triggers distal conformational changes that are subsequently communicated to the proximal His-411 heme a3 site. The 358 cm-1 mode has been found for the first time to accumulate with the 804 cm-1 mode in the peroxide reaction. These results indicate that the mechanism of oxygen reduction must be reexamined.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
23
pubmed:volume
278
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
18761-6
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2003
pubmed:articleTitle
Direct detection of Fe(IV)[double bond]O intermediates in the cytochrome aa3 oxidase from Paracoccus denitrificans/H2O2 reaction.
pubmed:affiliation
Department of Chemistry, University of Crete, 71409 Heraklion, Crete, Greece.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't