Linked Life Data

8218251

Source:http://linkedlifedata.com/resource/pubmed/id/8218251

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
44
pubmed:dateCreated
1993-12-16
pubmed:abstractText
We show here for the first time that a stable parallel double helix with Hoogsteen pairing can exist independently of the triple helix of which it is a component part. The experiments employ DNA oligonucleotides with mixed sequences of normal bases. These duplexes are distinct from previously reported ribopolynucleotide helices containing bulky substituents which prevent Watson-Crick pairing as well as from parallel duplexes with Donohue, or reversed Watson-Crick, pairing. Stoichiometry is established by mixing curves and gel electrophoresis. Tm depends linearly upon pH, increasing with acidity because of the need to protonate N3 of C. The Tm of the 20-mer studied here is 52 degrees C at pH 5.2 and 0.1 M NaCl. At pH above 6, the molecule rearranges to form an antiparallel duplex with imperfect Watson-Crick pairing and loops, and the Tm is then independent of pH. The CD spectrum of the parallel duplex is very similar to that of the corresponding triple helix but quite different from that of the Watson-Crick helix. The infrared spectrum in the double bond region closely resembles that of the triple helix but, as with the CD, is quite different from that of the Watson-Crick duplex. The infrared spectra of the duplex and triple helix are also nearly identical in the region form 800 to 1000 cm-1, which is sensitive to backbone conformation. The only symmetry element present is a pseudorotational axis coincident with the helix axis of the parallel duplex as well as with the axis of the corresponding triple helix.(ABSTRACT TRUNCATED AT 250 WORDS)
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
9
pubmed:volume
32
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
11802-9
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1993
pubmed:articleTitle
A novel DNA duplex. A parallel-stranded DNA helix with Hoogsteen base pairing.
pubmed:affiliation
Laboratory of Molecular Biology, NIDDK, National Institutes of Health, Bethesda, Maryland 20892.
pubmed:publicationType
Journal Article, Comparative Study