Sági J, Vorlícková M, Kypr J, Otvös L
Central Research Institute for Chemistry, Hungarian Academy of Sciences, Budapest.
Biochem Biophys Res Commun. 1989 Jun 30;161(3):1204-12. doi: 10.1016/0006-291x(89)91370-3.
Based on CD spectra, 2-amino-2'-deoxyadenosine-containing synthetic alternating DNA, poly(amino2dA-dt) undergoes a conformational transition from a B-form to a non-Z zig-zag form of DNA, called X, even under conditions where enzymes can work. Kinetic parameters of the E. coli Klenow DNA polymerase enzyme-catalyzed copying of both the B- and X-forms of poly(amino2dA-dT) have been determined. Binding affinity of X-DNA to the enzyme proved to be even higher than that of the B-DNA; primer-chain extension of X-poly(amino2dA-dT) was however hindered as compared to its B-form. This differential utilization of X-DNA versus B-DNA by a DNA polymerase is an in vitro enzymatic evidence of an unusual DNA conformation.
基于圆二色光谱，含2-氨基-2'-脱氧腺苷的合成交替DNA，聚（氨基2dA-dt）即使在酶能够发挥作用的条件下，也会经历从B型到一种称为X的非Z字形DNA构象的转变。已经测定了大肠杆菌Klenow DNA聚合酶催化复制聚（氨基2dA-dT）的B型和X型的动力学参数。事实证明，X-DNA与该酶的结合亲和力甚至高于B-DNA；然而，与B型相比，X-聚（氨基2dA-dT）的引物链延伸受到阻碍。DNA聚合酶对X-DNA和B-DNA的这种差异利用是一种异常DNA构象的体外酶学证据。
