COUNTERION EFFECTS ON THE PHYSICAL-PROPERTIES AND THE A-TRANSITION TO B-TRANSITION OF CALF-THYMUS DNA FILMS

被引:55
作者
LAVALLE, N [1 ]
LEE, SA [1 ]
RUPPRECHT, A [1 ]
机构
[1] UNIV STOCKHOLM,ARRHENIUS LAB,DIV PHYS CHEM,S-10691 STOCKHOLM,SWEDEN
关键词
D O I
10.1002/bip.360300903
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 report measurements of the water content and swelling of wet-spun films of Na-, K-, Rb-, and Cs-DNA as a function of relative humidity (rh). The water contents (number of water molecules per base pair of DNA) of these films are found to be quite similar, indicating that the identity of the counterion species is unimportant for the water content. Since the A to B transition for these DNAs occurs at different rhs, the corresponding water contents of the A to B transition are found to be quite different. These films swell as a function of rh in a very similar manner, implying that the changes in the intermolecular bonds in the different DNAs are similar. Dramatic changes are observed in the dimensions of the films above 84% rh for all types of DNA. Combining the water content and swelling measurements yields the dependence of the volume per base pair on water content. The volume per base pair is observed to be a nonlinear function of water content, indicating nonideal mixing of the water with the DNA.
引用
收藏
页码:877 / 887
页数:11
相关论文
共 52 条