Ivanov V I, Minchenkova L E, Schyolkina A K, Chernov B K, Yartsev A P, Kirpichnikov M P
Institute of Molecular Biology, USSR Academy of Sciences, Moscow.
J Biomol Struct Dyn. 1985 Dec;3(3):521-7. doi: 10.1080/07391102.1985.10508439.
Conformations of the synthetic deoxyoligonucleotide 17 base pairs long, which is an OR3 operator of lambda phage, and of its 9-b.p. fragment were studied by the circular dichroism method (CD). The regions of stability of the double-stranded state were determined for these duplexes. A comparison of the CD spectra for these oligonucleotides with the CD for a lengthy DNA showed the conformation of these short DNA pieces to belong to the B-family. A cooperative change in the CD spectra is observed in trifluoroethanol (TFE) solutions at a TFE concentration specific for each oligonucleotide, which is supposed to stem from a B to A transition. The length of the fragment was found to affect the ability for the B-A transition. The transition into the A form is hindered by 13% TFE for the short 9-nucleotide in comparison with the 17-nucleotide. We suggest that this is due to the B form stabilization by terminal base pairs (B-phility of the ends).
研究了作为λ噬菌体OR3操纵基因的17个碱基对长的合成脱氧寡核苷酸及其9个碱基对片段的构象，采用圆二色性方法（CD）。确定了这些双链体双链状态的稳定区域。将这些寡核苷酸的CD光谱与长链DNA的CD光谱进行比较，表明这些短DNA片段的构象属于B族。在三氟乙醇（TFE）溶液中，在每种寡核苷酸特有的TFE浓度下，观察到CD光谱的协同变化，这被认为源于从B型到A型的转变。发现片段长度会影响B-A转变的能力。与17个核苷酸相比，短的9个核苷酸的A形式转变受到13%TFE的阻碍。我们认为这是由于末端碱基对使B型稳定（末端的B亲合性）。
