Riazance J H, Johnson W C, McIntosh L P, Jovin T M
Department of Biochemistry and Biophysics, Oregon State University, Corvallis 97331.
Nucleic Acids Res. 1987 Sep 25;15(18):7627-36. doi: 10.1093/nar/15.18.7627.
Circular dichroism spectra are extended into the vacuum UV to about 178 nm for four polydeoxynucleotides of various sequences capable of assuming the left-handed Z form. It is found that each of these polymers, including those with brominated bases and those with the four different bases, have a characteristic negative feature at short wavelengths when in the Z form. In contrast, the B form only has a positive band between 180 and 200 nm. Furthermore, a blue shift of the short wavelength crossover is diagnostic of the B- to Z-form transition for all polymers studied so far. These results confirm that poly[d(A-C).d(G-T)] can assume the Z form in solution at low concentration.
对于四种能够呈现左手Z型构象的不同序列的聚脱氧核苷酸,圆二色光谱被扩展到真空紫外区,直至约178纳米。结果发现,这些聚合物中的每一种,包括那些带有溴化碱基的聚合物以及含有四种不同碱基的聚合物,在呈Z型构象时在短波长处都有一个特征性的负峰。相比之下,B型构象仅在180至200纳米之间有一个正峰。此外,到目前为止,对于所有研究的聚合物而言,短波长交叉点的蓝移是B型向Z型转变的诊断依据。这些结果证实,聚[d(A - C).d(G - T)]在低浓度溶液中能够呈现Z型构象。