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One left‐handed strand in DNA‐oligonucleotide complexes?
Author(s) -
Gago Federico,
Richards W.G.
Publication year - 1989
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(89)80483-1
Subject(s) - oligonucleotide , left handed , dna , biophysics , chemistry , crystallography , biology , physics , biochemistry , optics
A single strand of oligonucleotide can bind to double helical DNA under certain conditions. This must involve some unwinding of the original double helix in a process leading to the formation of a three‐stranded region. The free energy for such an entropically unlikely reaction may come from a change in the degree of supercoiling of the original DNA. The conformation of the triple strand is investigated here using computer graphics and molecular mechanics calculations. It is suggested that on binding the oligonucleotide (strand 3) to two paired strands (1 and 2) in a supercoiled DNA molecule, strand 2 might adopt a left‐handed conformation whilst strand 1 and strand 3 pair in the normal Watson‐Crick B‐configuration.