Lortkipanidze G B, Evdokimov Iu M, Kadykov V A, Varshavskiĭ Ia M
Mol Biol (Mosk). 1980 Nov-Dec;14(6):1378-86.
The conditions (mol. weight of PEG, ionic strength) of formation of double-stranded RNA (dsRNA) compact particles in water-salt solutions, containing poly(ethylene glycol) (PEG) have been determined. It has been shown, that in solutions of mild ionic strength (approximately 0,3) the compact particles of dsRNA are characterized by an intense positive CD-band (lambda 270 nm), but in solutions of high ionic strength (1,0-1,5)--by intense positive or negative CD-bands (lambda 270 nm). The heating of the solutions of a high ionic strength, containing the compact particles with negative CD-bands is accompanied by the change of sign of CD-band. The same effect is observed in the case of decrease of the ionic strength of the solutions. "Melting" of compact particles as revealed by the CD-method occurs prior to the melting of the secondary structure of dsRNA. These data show, that the intense CD-bands reflect the ordered arrangement of the chromophores of polynucleotide chain in compact particles. The reasons of change of the sign of the CD-bands are discussed.
已确定在含有聚乙二醇（PEG）的水盐溶液中形成双链RNA（dsRNA）致密颗粒的条件（PEG的分子量、离子强度）。结果表明，在中等离子强度（约0.3）的溶液中，dsRNA的致密颗粒具有强烈的正圆二色性带（λ270nm），但在高离子强度（1.0 - 1.5）的溶液中，则具有强烈的正或负圆二色性带（λ270nm）。加热含有负圆二色性带致密颗粒的高离子强度溶液会伴随圆二色性带符号的变化。在降低溶液离子强度的情况下也观察到相同的效果。通过圆二色性方法揭示的致密颗粒“解链”发生在dsRNA二级结构解链之前。这些数据表明，强烈的圆二色性带反映了致密颗粒中多核苷酸链发色团的有序排列。文中讨论了圆二色性带符号变化的原因。
