Linked Life Data

1423837

Source:http://linkedlifedata.com/resource/pubmed/id/1423837

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
10
pubmed:dateCreated
1992-11-27
pubmed:abstractText
Substitution of a methyl group in the 11-position of benzo[a]pyrene (B[a]P) enhances its carcinogenicity. An X-ray crystallographic determination of the three-dimensional structure of 11-methylbenzo[a]pyrene (11-MeB[a]P) shows that steric overcrowding in the bay region is relieved somewhat by distortions of the bay-region bond angles in the plane of the ring system. A comparison with the structure of 7,12-dimethylbenz[a]anthracene (DMBA), which shows out-of-plane distortions to relieve such strain, shows that, in general, H...H intramolecular interactions between neighboring rings in a polycyclic aromatic hydrocarbon are the primary determinants of the nature of the molecular distortions as a result of steric overcrowding (mainly in-plane for 11-MeB[a]P and mainly out-of-plane for DMBA). The 11-MeB[a]P molecule exhibits considerable flexibility as evidenced by slightly different conformations in the two molecules found in the asymmetric unit of the crystal. One molecule is fairly flat with bond angle distortions in the bay region, while the other is slightly buckled as a result of some twist (15 degrees) in the bay region. Computer modeling indicates that steric overcrowding as a result of the bay-region 11-methyl group may affect the conformation of the ring that bears the diol and epoxide groups in the anti-diolepoxide. The nature of this distortion may, in turn, provide a clue to the reason for the greater carcinogenicity of B[a]P when methylated at the 11-position in the non-benzo bay region site. In addition, the 11-methyl group, because of its bulk, may affect the orientation of the polycyclic hydrocarbon as it lies between the nucleic-acid bases when covalently bound to DNA.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0143-3334
pubmed:author
pubmed:issnType
Print
pubmed:volume
13
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1775-82
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1992
pubmed:articleTitle
11-Methylbenzo[a]pyrene: bay region distortions.
pubmed:affiliation
University of New Mexico, Albuquerque 87131.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't