Linked Life Data

1310611

Source:http://linkedlifedata.com/resource/pubmed/id/1310611

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
1992-3-16
pubmed:abstractText
Imino proton exchange studies are reported on the complexes formed by bisintercalation of luzopeptin around the two central A.T pairs of the d(CCCATGGG) and d(AGCATGCT) duplexes and of echinomycin around the two central C.G pairs of the d(AAACGTTT) and d(CCAAACGTTTGG) duplexes. The depsipeptide backbone of the drugs occupies the minor groove of the complexes at the bisintercalation site. The exchange time of the amide protons of the depsipeptide rings provides a lower estimate of the complex lifetime: 20 min at 15 degrees C for the echinomycin complexes and 4 days at 45 degrees C for the luzopeptin complexes. The exchange time of imino protons is always shorter than the complex lifetime. Hence, base pairs open even within the complexed oligomers. For the two base pairs sandwiched between the aromatic rings of the drug, the base-pair lifetime is strongly increased, and the dissociation constant is correspondingly reduced. Hence, the lifetime of the open state is unchanged. This suggests similar open states in the free duplex and in the complex. In contrast to the sandwiched base pairs, the base pairs flanking the intercalation site are not stabilized in the complex. Thus, the action of the bisintercalating drug may be compared to a vise clamping the inner base pairs. Analysis suggests that base-pair opening may require prior unwinding or bending of the DNA duplex.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
11
pubmed:volume
31
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1407-15
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1992
pubmed:articleTitle
Proton exchange in DNA-luzopeptin and DNA-echinomycin bisintercalation complexes: rates and processes of base-pair opening.
pubmed:affiliation
Groupe de Biophysique, Ecole Polytechnique, Palaiseau, France.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't