A stable complex between homopyrimidine oligomers and the homologous regions of duplex DNAs
- 1 January 1988
- journal article
- research article
- Published by Oxford University Press (OUP) in Nucleic Acids Research
- Vol. 16 (5), 2165-2187
- https://doi.org/10.1093/nar/16.5.2165
Abstract
When plasmid DNA duplexes carrying the regular homopurine-homopyrimidine inserts(dGA) .cntdot. (dTC)n and (dG)n .cntdot. (dC)n are preincubated with homologous labeled oligo(dPy) ((dTC)n and (dC)n respectively) at acid pH, the label co-electrophoreses with the duplex DNA. Thus, a very strong complex is formed. Complementary oligo(dPu) does not form a complex under these conditions. No binding is observed for oligo(dPy) with non-homologous inserts as well as with vector plasmids without inserts. The complex is formed equally well with linear, nicked or superhelical DNA. The complex is not detected at pH > 6. Complex formation leads to very little, if any, unwinding of the duplex. The observed complex appears to be the Py .cntdot. Pu .cntdot. Py triplex consisting of TAT and CGC+ base-triads with protonated cytosines. Two-dimensional gel electrophoresis patterns show that the presence of homologous oligo(dPy) destabilizes the formation of the H form.This publication has 24 references indexed in Scilit:
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