Zimmer C, Kakiuchi N, Guschlbauer W
Nucleic Acids Res. 1982 Mar 11;10(5):1721-32. doi: 10.1093/nar/10.5.1721.
Six polynucleotide duplexes containing polydeoxyadenylic acid, polyadenylic acid or poly-2'-deoxy-2'-fluoro-adenylic acid in one strand, and polydeoxyuridylic acid or polydeoxythymidylic acid in the other strand have been studied by circular dichroism, ionic strength dependence of melting temperatures and binding of the DNA specific antibiotic netropsin. Circular dichroism spectra of (dA)n . (dT)n and (dA)n . (dU)n indicated the presence of the B-form of DNA, while those of (dAfl)n . (dT)n and (rA)n . (dT)n (and the corresponding (dU)n hybrids) indicated the presence of the A-form. (dAfl)n . (dT)n and (dAfl)n . (dU)n bound netropsin only slightly less than the (dA)n containing duplexes, while replacement by (rA)n decreased netropsin binding to a large degree. Since netropsin requires B-DNA for binding, it is concluded that the A to B transition is facilitated in the case of fluorine substitution in the sugar moiety, while the 2'-OH group greatly limits this conformational change.
已通过圆二色性、熔解温度的离子强度依赖性以及DNA特异性抗生素纺锤菌素的结合,对六条多核苷酸双链体进行了研究。这六条双链体中,一条链含有聚脱氧腺苷酸、聚腺苷酸或聚-2'-脱氧-2'-氟腺苷酸,另一条链含有聚脱氧尿苷酸或聚脱氧胸苷酸。(dA)n.(dT)n和(dA)n.(dU)n的圆二色光谱表明存在B型DNA,而(dAfl)n.(dT)n和(rA)n.(dT)n(以及相应的(dU)n杂交体)的圆二色光谱表明存在A型DNA。(dAfl)n.(dT)n和(dAfl)n.(dU)n结合纺锤菌素的能力仅略低于含(dA)n的双链体,而用(rA)n替代则大大降低了纺锤菌素的结合能力。由于纺锤菌素需要B-DNA才能结合,因此可以得出结论,在糖部分进行氟取代的情况下,A向B的转变更容易发生,而2'-羟基则极大地限制了这种构象变化。