Linked Life Data

21553704

Source:http://linkedlifedata.com/resource/pubmed/id/21553704

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2011-5-5
pubmed:abstractText
The N-terminal, extracellular regions of eukaryotic high affinity copper transport (Ctr) proteins vary in composition of the Cu(i) binding amino acids: methionine, histidine, and cysteine. To examine why certain amino acids are exploited over others in Ctrs from different organisms, the relative Cu(i) binding affinity and the dependence of binding on pH were examined for 3 peptides of the sequence MG(2)XG(2)MK, where X is either Met, His, or Cys. Cu(i) affinity was examined using an ascorbic acid oxidation assay, an electrospray ionization mass spectrometry technique, and spectrophotometric titration with a competitive Cu(i) chelator. The relative affinities of the peptides with Cu(i) reveal a trend whereby Cys > His > Met at pH 7.4 and Cys > Met > His at pH 4.5. Ligand geometry and metric parameters were determined with X-ray absorption spectroscopy. Susceptibility of the peptides to oxidation by hydrogen peroxide and copper-catalyzed oxidative conditions was evaluated by mass spectrometry. These results support hypotheses as to why certain Cu(i) binding amino acids are preferred over others in proteins expressed at different pH and exposed to oxidative environments. The results also have implications for interpreting site-directed mutagenesis studies aimed at identifying copper binding amino acids in copper trafficking proteins.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
1756-591X
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
3
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
61-73
pubmed:meshHeading
pubmed:year
2011
pubmed:articleTitle
A comparison of methionine, histidine and cysteine in copper(I)-binding peptides reveals differences relevant to copper uptake by organisms in diverse environments.
pubmed:affiliation
Department of Chemistry, Duke University, P.O. Box 90346,Durham, NC 27708-0346, USA.
pubmed:publicationType
Journal Article, Comparative Study