Linked Life Data

8180233

Source:http://linkedlifedata.com/resource/pubmed/id/8180233

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1994-6-15
pubmed:abstractText
The pulsed EPR technique of electron spin echo envelope modulation (ESEEM) has been utilized to examined both the 'very rapid' and 'desulfo inhibited' Mo(V) signals of xanthine oxidase in order to probe for magnetic interactions with nitrogen, phosphorus and hydrogen nuclei. No 14N modulation is observed in the 'desulfo inhibited' EPR signal, indicating that histidine is unlikely to be a ligand to molybdenum. Strong 14N modulation is observed in the 'very rapid' EPR signal formed with 2-hydroxy-6-methylpurine substrate bound to molybdenum. We interpret this modulation as arising from nitrogens of the bound purine substrate. This interpretation is consistent with the present evidence indicating that the purine ring present in the species giving rise to the 'very rapid' EPR signal is coordinated to the molybdenum center through the catalytically introduced hydroxyl group. No modulation is observed from non-exchangeable deuterons in experiments performed with deuterated 2-hydroxy-6-methylpurine. Given the signal-to-noise level of the spectra, the lack of modulation indicates that each of the substrate methyl group deuterons is greater than 4.9 A from the Mo(V). The deuteron removed from the C8 position in the binding of the substrate is also exchanged to a site or sites greater than 4.9 A from the Mo(V) in the time-course of sample preparation. Moderately deep deuteron modulation arises from exchangeable sites. A large portion of this modulation can be accounted for by the exchangeable N7 deuteron of the 2-hydroxy-6-methylpurine substrate, which we estimate to be approximately 3.2 A from the molybdenum. Additional exchangeable deuterons on the protein or within the buffer must be present within 5 A of the molybdenum to account for the remaining modulation. No modulation from weakly-coupled 31P nuclei is observed in either the 'desulfo inhibited' or 'very rapid' EPR signal.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0006-3002
pubmed:author
pubmed:issnType
Print
pubmed:day
18
pubmed:volume
1185
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
284-94
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
1994
pubmed:articleTitle
Electron spin echo envelope modulation spectroscopy of the molybdenum center of xanthine oxidase.
pubmed:affiliation
Department of Chemistry, University of California Davis 95616.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S.