Linked Life Data

3971985

Source:http://linkedlifedata.com/resource/pubmed/id/3971985

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1985-4-9
pubmed:abstractText
We present a detailed conformational study of 15N-labelled actinomycin D in different organic solvents using 1H, 15N and two-dimensional (2D) NMR techniques at 30.4 MHz and 50.6 MHz. The assignment of the threonine and valine 15N resonances to the individual residues on the alpha- or beta-lactone rings was achieved via heteronuclear shift-correlated 2D NMR experiments. The solvent perturbation studies allow an estimation of the solvent accessibility of the nitrogens and carbonyl groups. Evidence is presented that the pentapeptide rings of actinomycin D have different conformations in polar and in apolar solvents. The chromophoric N10 is efficiently solvent-protected, the solvent-dependence of its 15N resonance resulting from solvent interactions at other positions of the molecule and from solvent-dependent changes in the twisting of the chromophoric system. The chromophoric 2-amino nitrogen is shown to exhibit a strong sp2 character due to the formation of a conjugated system with the carbonyl group at C1. Such a conjugation requires a non-planar chromophoric ring system. Additionally, a hydrogen bond connecting the 2-amino and the 1-carbonyl group was detected. In some solvents, two resonances appear for the 2-amino nitrogen implying the presence of the 2-amino group in two different conformations. The possible implications of the non-planarity of the chromophore for the intercalation process and for the biological activity of the drug are discussed.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0014-2956
pubmed:author
pubmed:issnType
Print
pubmed:day
1
pubmed:volume
147
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
313-24
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
1985
pubmed:articleTitle
Intramolecular interactions, mesomerism and dynamics in actinomycin D studied by 15N NMR spectroscopy.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't