Preparation and melting of single strand circular DNA loops.
AUTOR(ES)
Wemmer, D E
RESUMO
A method for preparation of single strand DNA circles of almost arbitrary sequence is described. By ligating two sticky ended hairpins together a linear duplex is formed, closed at both ends by single stranded loops. The melting characteristics of such loops are investigated using optical absorbance and NMR. It is shown by comparison with the corresponding linear sequence (closed circle minus the end loops) that the effects of end fraying and the strand concentration dependence of the melting temperature are eliminated in the circular form. Over the concentration range examined (0.5 to 2.0 micromolar strands), the circular DNA has a monophasic melting curve, while the linear duplex is biphasic, probably due to hairpin formation. Since effects of duplex to single strands dissociation do not contribute to melting of the circular molecules (dumbells), these DNAs present a realistic experimental model for examining local thermal stability in DNA.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=322156Documentos Relacionados
- Distribution of initial and persistent 2-acetylaminofluorene-induced DNA adducts within DNA loops.
- Interplay of structure and disorder in cochaperonin mobile loops.
- Scission of RNA by the chemical nuclease of 1,10-phenanthroline-copper ion: preference for single-stranded loops.
- Enterotoxic activity of Klebsiella oxytoca cytotoxin in rabbit intestinal loops.
- A putative zinc-binding protein on lampbrush chromosome loops.
