Comparison of magnetic properties of DNA-cetyltrimethyl ammonium complex with those of natural DNA

We prepared the DNA-cetyltrimethyl ammonium complex, as well as the same complex intercalated with stable organic free radicals, and studied their magnetic properties by electron magnetic resonance （EMR） spectroscopy and by measuring the magnetization on a superconducting quantum interference device...

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Bibliographic Details
Published in:Science China. Chemistry 2012-05, Vol.55 (5), p.814-821
Main Authors: Kwon, Young-Wan, Choi, Dong Hoon, Jin, Jung-Il, Lee, Chang Hoon, Koh, Eui Kwan, Grote, James G.
Format: Article
Language:English
Subjects:
CD光谱
Chemistry
Chemistry and Materials Science
Chemistry/Food Science
Free radicals
Magnetic properties
Magnetic resonance
Magnetization
Spectrum analysis
Superconducting quantum interference devices
十六烷基三甲基铵
双链DNA
天然
有机自由基
电子病历
磁学性质
超导量子干涉器件
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Summary:We prepared the DNA-cetyltrimethyl ammonium complex, as well as the same complex intercalated with stable organic free radicals, and studied their magnetic properties by electron magnetic resonance （EMR） spectroscopy and by measuring the magnetization on a superconducting quantum interference device （SQUID）. The UV-vis and CD spectra of DNA-quaternary alkyl ammonium complex （DNA--Q＋） in organic solvent clearly demonstrated that it retained the double helical B-form conformation. The interhelical spacing of double strand DNA （dsDNA） increased when the counter ions （Na＋） of phosphate groups of the natural DNA were replaced with the long alkyl quaternary ammonium groups. The inter-helical distance of DNA-cetyltrimethyl ammonium （CTMA） was 39.1  as confirmed by X-ray diffractometry. In general, the magnetization of the DNA-CTMA complex solid was found to be significantly lower than that of natural DNA. Moreover, intercalation of the complex with stable organic free radicals did not improve magnetization, which again was in marked contrast to natural DNA. EMR spectroscopic behavior of the complex in the solid state also was quite different from that of natural DNA： The unique broad EMR signal of natural DNA in the low field region with g-value greater than 10 disappeared in the DNA-CTMA complex.
ISSN:1674-7291
1869-1870
DOI:10.1007/s11426-012-4507-z