Effects of polyamines on the thermal stability and formation kinetics of DNA duplexes with abnormal structure

Ming Hon Hou, Shwu Bin Lin, Jeu Ming P. Yuann, Wei Chen Lin, Andrew H.J. Wang, Lou Sing Kan

研究成果: 雜誌貢獻文章同行評審

74 引文 斯高帕斯(Scopus)

摘要

The effects of ions (i.e. Na+, Mg2+ and polyamines including spermidine and spermine) on the stability of various DNA oligonucleotides in solution were studied. These synthetic DNA molecules contained sequences that mimic various cellular DNA structures, such as duplexes, bulged loops, hairpins and/or mismatched base pairs. Melting temperature curves obtained from the ultraviolet spectroscopic experiments indicated that the effectiveness of the stabilization of cations on the duplex formation follows the order of spermine > spermidine > Mg2+ > Na+ > Tris-HCl buffer alone at pH 7.3. Circular dichroism spectra showed that salts and polyamines did not change the secondary structures of those DNA molecules under study. Surface plasmon resonance (SPR) observations suggested that the rates of duplex formation are independent of the kind of cations used or the structure of the duplexes. However, the rate constants of DNA duplex dissociation decrease in the same order when those cations are involved. The enhancement of the duplex stability by polyamines, especially spermine, can compensate for the instability caused by abnormal structures (e.g. bulged loops, hairpins or mismatches). The effects can be so great as to make the abnormal DNAs as stable as the perfect duplex, both kinetically and thermodynamically. Our results may suggest that the interconversion of various DNA structures can be accomplished readily in the presence of polyamine. This may be relevant in understanding the role of DNA polymorphism in cells.

原文英語
頁(從 - 到)5121-5128
頁數8
期刊Nucleic Acids Research
29
發行號24
DOIs
出版狀態已發佈 - 12月 24 2001
對外發佈

ASJC Scopus subject areas

  • 遺傳學

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