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Sequence dependent electrophoretic mobilities and melting temperatures for A-T containing oligodeoxyribonucleotides
Nucleic Acids Research
|January 12, 1987
Summary
Oligonucleotide melting temperatures increase with longer A-T sequences. DNA sequence affects mobility on gels, with bends at continuous A or T bases influencing movement.
Area of Science:
- Molecular Biology
- Biochemistry
- Oligonucleotide Chemistry
Background:
- Self-complementary A-T containing dodecamer oligonucleotides are crucial in molecular biology.
- Understanding their properties under varying conditions is key to DNA structure and function studies.
Purpose of the Study:
- To investigate the electrophoretic mobilities and thermal melting properties of A-T containing dodecamer oligonucleotides.
- To determine how sequence variations, specifically nonalternating A-T tracts, affect these properties.
Main Methods:
- Electrophoretic mobility analysis on acrylamide gels under denaturing and duplex-forming conditions.
- Thermal melting property analysis (melting temperature determination).
Main Results:
- Melting temperature increased with the length of nonalternating A-T sequences, with d(A6T6) showing a ~12°C higher melting temperature than the alternating oligomer.
- Under denaturing conditions, all oligomers exhibited similar electrophoretic mobility.
- Under duplex-forming conditions, significant sequence-dependent mobility differences were observed, with d(A2T2)3 showing the greatest mobility and d(A-T)6 and d(A6-T6) showing the least.
Conclusions:
- The length of nonalternating A-T sequences directly impacts oligonucleotide thermal stability.
- Sequence-dependent DNA bending at junctions of continuous A or T bases explains observed electrophoretic mobility variations.
- These findings provide insights into DNA structural dynamics and sequence recognition.