| Autor: |
Kalisch, Bernd W, Germann, Markus W, van de Sande, J.H |
| Zdroj: |
FEBS Letters; May 1998, Vol. 427 Issue: 2 p301-304, 4p |
| Abstrakt: |
Alternating polypurine d(GA)nsequences exhibit a considerable polymorphism. Here we report that α d(GA)⋅d(GA) sequences form an antiparallel stranded duplex DNA at neutral pH. The spectroscopic, electrophoretic and thermodynamic properties of the α/β chimeric oligodeoxynucleotide, 5′‐d(GA)4(T)4α d(AG)4T‐3′, support the formation of a hairpin structure with antiparallel strands in the stem. The optical properties of this novel antiparallel structure are different from the parallel stranded homoduplex formed by d(GA)G7. This α/β hairpin has a remarkably high Tmof 44.5°C in 0.4 M NaCl with a van't Hoff enthalpy comparable to that of a parallel d(GA)nduplex. Base pairing was confirmed by T4polynucleotide ligase catalyzed joining of the α/β hairpin to an antiparallel bimolecular duplex and by non‐denaturing gel electrophoresis using duplexes containing sequence constraints. Both support the presence of αG‐G and αA‐A base pairing in the antiparallel 5′‐d(GA)4(T)4α d(AG)4T‐3′ intramolecular duplex. This study adds to the polymorphic nature of alternating d(GA)nsequences as well as providing novel homopurine base pairing approaches for probing polypurine polypyrimidine sequences. |
| Databáze: |
Supplemental Index |
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