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Parallel and antiparallel triple helices with G,A‐containing third strands
Author(s) -
Porumb Horea,
Gousset Hervé,
Taillandier Eliane
Publication year - 1999
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/(sici)1522-2683(19990301)20:3<511::aid-elps511>3.0.co;2-6
Subject(s) - antiparallel (mathematics) , triple helix , oligonucleotide , chemistry , crystallography , guanine , nucleotide , stereochemistry , dna , physics , biochemistry , quantum mechanics , magnetic field , gene
A triple helix, formed by a 13 nucleotide (nt) all‐purine oligonucleotide, containing six contiguous guanines, oriented parallel to a homopurine strand present in the polypurine tract of Friend leukemia virus, was obtained in 0.1 M LiCl. Its dissociation constant at 25 o C, given by electrophoretic titration, of the order of 50 n M , is at least ten times lower than that of the corresponding antiparallel triplex formed on the same target. At 4 o C, the parallel orientation of the homopurine strands is favored to the point that the guanine block of 6 nt, present in the ‘antiparallel’ oligonucleotide, attaches in a parallel fashion to the corresponding block in the target strand, to generate a partial, parallel triplex, that coexists with the antiparallel one.