Linked Life Data

20121242

Source:http://linkedlifedata.com/resource/pubmed/id/20121242

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
45
pubmed:dateCreated
2010-11-12
pubmed:abstractText
The photophysical and photochemical behavior of a series of hairpin-forming DNA conjugates possessing a 5'-tethered pyrenecarboxamide chromophore and one or two bromouracil bases has been investigated. Quenching of the pyrene fluorescence and transient absorption spectra characteristic of the pyrene cation radical are observed only when bromouracil is located at the first or second base pair position nearest to the point of pyrene attachment. These observations are consistent with an intercalated structure for these conjugates in which pyrene is adjacent to the second base pair. Selective quenching of singlet pyrene by bromouracil but not by thymine is consistent with the free energy for charge separation estimated using Weller's equation. Low quantum yields for loss of bromide when bromouracil is not adjacent to pyrene are attributed to inefficient charge separation via either a multistep electron transport or a single-step superexchange mechanism. Quantum yields are only weakly dependent upon the distance between pyrene and bromouracil, as expected for a multistep electron transport mechanism. Loss of bromide from conjugates possessing two bromouracils occurs sequentially. For adjacent bromouracils, competitive loss of bromide from both bromouracils is observed, whereas for nonadjacent bromouracils loss of bromide from the proximal bromouracil occurs prior to any loss from the distal bromouracil, consistent with a slower rate constant for electron transport vs loss of bromide.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
1520-5207
pubmed:author
pubmed:issnType
Electronic
pubmed:day
18
pubmed:volume
114
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
14265-72
pubmed:meshHeading
pubmed:year
2010
pubmed:articleTitle
Dynamics and efficiency of electron injection and transport in DNA using pyrenecarboxamide as an electron donor and 5-bromouracil as an electron acceptor.
pubmed:affiliation
Department of Chemistry, Northwestern University, Evanston, Illinois 60208-3113, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S.