Linked Life Data

6466624

Source:http://linkedlifedata.com/resource/pubmed/id/6466624

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
13
pubmed:dateCreated
1984-9-26
pubmed:abstractText
The imino-amino tautomeric equilibrium of the promutagenic adenosine analogue N6-methoxy-2',3',5'-tri-O-methyladenosine [OMe6A(Me)3], in solvents of various polarities, has been studied with the aid of 1H and 13C NMR spectroscopy. The high energy barrier (free enthalpy delta G = 80 +/- 5 kJ X mol-1) between the two tautomeric species renders possible direct observation of the independent sets of all 1H and 13C signals from each of them. The equilibrium ranges from 10% imino in CCl4 to 90% in aqueous medium. Thermodynamic parameters, including energy barriers and lifetimes, were calculated from the temperature dependence of the equilibrium. Essentially similar results prevail for the promutagenic N6-hydroxy analogue. The conformations of the sugar moieties, and of the base about the glycosidic bond, for both tautomers are similar to those for adenosine. The conformation of the exocyclic N6-OCH3 group, which determines the ability of each species to form planar associates (hydrogen-bonded base pairs), has also been evaluated. Formation of autoassociates of OMe6A(Me)3 and of heteroassociates with the potentially complementary 2',3',5'-tri-O-methyluridine and -cytidine, in chloroform solution, was also investigated. The amino form base pairs with uridine and the imino form with cytidine. Formation of a complementary base pair by a given tautomeric species was accompanied by an increase of up to 10% in the population of this species and a concomitant decrease in population of the other species.(ABSTRACT TRUNCATED AT 250 WORDS)
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
19
pubmed:volume
23
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2906-13
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1984
pubmed:articleTitle
Hydroxylamine and methoxyamine mutagenesis: displacement of the tautomeric equilibrium of the promutagen N6-methoxyadenosine by complementary base pairing.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't