THE FLEXIBILITY OF A-FORM DNA

被引:16
作者
CHARNEY, E
CHEN, HH
RAU, DC
机构
[1] GEORGE MASON UNIV, DEPT CHEM, FAIRFAX, VA 22030 USA
[2] NIDDK, BIOCHEM METAB LAB, BETHESDA, MD 20892 USA
基金
美国国家科学基金会;
关键词
D O I
10.1080/07391102.1991.10507917
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
We have determined the rise per base pair and persistence length of A-form DNA in trifluoroethanol solutions for fragments 350-900 base pairs in length that best describe rotational diffusion coefficients determined by transient electric birefringence. The 2.6 A spacing between base pairs found in crystal and fiber A-form structures is preserved in solution. The persistence length is about 1500 A, or about three times longer than for B-form DNA. There is no apparent electrostatic contribution to the persistence length in the salt concentration range 0.2-2.0 mM Na cacodylate. This suggests an even closer association between DNA and its neutralizing counterions than predicted by condensation theory, perhaps due to a sheath of trifluoroethanol excluded water surrounding the A-form helix.
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页码:353 / 362
页数:10
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