Linked Life Data

16490387

Source:http://linkedlifedata.com/resource/pubmed/id/16490387

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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
2006-6-9
pubmed:abstractText
Results of the steady-state fluorescence, anisotropy and FRET measurements of G-quadruplex formation in the presence of selected cations (Li(+), Na(+), K(+), NEt(4)(+) and Mg(2+)) are reported. Three different fluorescent oligonucleotides with human telomeric sequence labeled with fluorescein (FAM) and tetramethylrhodamine (TAMRA) were investigated: a dual-labeled 21-mer denoted as PSO (Potassium Sensing Oligonucleotide) and two 5'- and 3'- single-labeled probes, FAM-21 and 21-TAMRA, respectively. The fluorescence signal of FAM-21 increased significantly for all systems and the fluorescence enhancement was comparable in magnitude for monovalent cations but it was more pronounced for Mg(2+) cation. This phenomenon was attributed to the protolytic equilibria of FAM affected by the variation in ionic strength. On the other hand, fluorescence of TAMRA was enhanced selectively by Na(I) cation that was explained by the dequenching of TAMRA emission originated from the peculiarity of the basket-type structure of Na(I)-quadruplex. Anisotropy of FAM-21 (but not 21-TAMRA) appeared to be sensitive to the G-quadruplex formation, showing significant increase with an increase in cation concentration and indicating some restrictions in rotational depolarization of FAM. FRET experiments revealed that all tested cations caused quenching of FAM fluorescence in PSO, but only Na(+) and K(+) ions produced sensitized emission of TAMRA acceptor. Higher FRET efficiency observed in the presence of sodium ion was attributed to the specific spectral factor and steric interactions in the basket-type Na(I)-quadruplex.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
1386-1425
pubmed:author
pubmed:issnType
Print
pubmed:volume
64
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
835-43
pubmed:meshHeading
pubmed:year
2006
pubmed:articleTitle
Fluorescence anisotropy and FRET studies of G-quadruplex formation in presence of different cations.
pubmed:affiliation
Department of Analytical Chemistry, Faculty of Chemistry, A. Mickiewicz University, Grunwaldska 6, 60-780 Poznan, Poland. juskowia@amu.edu.pl
pubmed:publicationType
Journal Article