Linked Life Data

2856029

Source:http://linkedlifedata.com/resource/pubmed/id/2856029

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1990-3-20
pubmed:abstractText
Plasmid pEJ4, which is a derivative of pUC19 containing an insert with 60-bp-long homopurine.homopyrimidine tract from sea urchin P. miliaris histone gene spacer, was studied by chemical probes of the DNA structure osmium tetroxide and glyoxal. The former probe reacts with pyrimidine bases, while the latter forms a stable product only with guanine residues. These probes can thus be applied as specific probes for the homopyrimidine and homopurine strands, respectively. At pH 6.0 the site-specific modification of the homopurine.homopyrimidine tract by both probes was observed at native superhelical density of the plasmid. In the linear plasmid under the same conditions this modification was absent; it appeared, however, at more acid pH values. In supercoiled DNA the hypersensitivity of the homopurine.homopyrimidine tract to osmium tetroxide did not substantially change when pH was decreased from 6.0 to 4.0. Changes in NaCl concentration at pH 4.5 did not influence the hypersensitivity to osmium tetroxide; at pH 6.0 this hypersensitivity decreased with increasing NaCl concentration. These results thus show that the chemical probes recognize an unusual protonated structure containing unpaired bases or non-Watson-Crick base pairs. At pH 5.6 the site-specific modification occurred at or near to the middle of the homopurine.homopyrimidine tract, suggesting that a hairpin may be involved in the unusual structure under the given conditions. From the models suggested so far for the unusual structure of homopurine.homopyrimidine tracts our results fit best the protonated triplex H form suggest by V.I. Lyamichev, S.M. Mirkin and M.D. Frank-Kamenetskii, J. Biomol. Struct. Dyn. 3,667 (1986).
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0739-1102
pubmed:author
pubmed:issnType
Print
pubmed:volume
5
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
283-96
pubmed:dateRevised
2006-5-1
pubmed:meshHeading
pubmed:year
1987
pubmed:articleTitle
Unusual protonated structure in the homopurine.homopyrimidine tract of supercoiled and linearized plasmids recognized by chemical probes.
pubmed:affiliation
Institute of Biophysics Czechoslovak Academy of Sciences, Brno.
pubmed:publicationType
Journal Article