Lesnik E A, Agranovich I M, Maslova R N, Varshavskiĭ Ia M
Mol Biol (Mosk). 1987 Mar-Apr;21(2):422-7.
The rate constants of 1H----3H exchange between water and C8H-groups of purinic residues of alternating polynucleotides: poly[d(A-T)].poly[d(A-T)] (I), poly[d(G-C)].poly[d(G-C)] (II), poly[d(A-C)].poly[d(G-T)] (III) and homopolynucleotides: poly(dA).poly(dt) (IV), poly(dG).poly(dC) (V), as well as DNA E. coli, was determined in 0.15 M NaCl at 25 degrees C. The retardation of exchange observed at these conditions (compared to that of the B-form DNA) is in agreement with the model of B-alternating structure for the (I) and is attributed to the co-existence of B- and A-conformers for the (V) in solution. Absence of distinguishable differences in exchange rate constants for purinic residues of the (II), (III) and (IV) (compared to that of the B-form DNA) evidences that conformations of these polynucleotides in solution are similar to "canonical" B-form DNA and don't correlate with the model of "heteronomous" DNA which was proposed for (IV).
在25℃下，于0.15M NaCl溶液中测定了交替多核苷酸：聚[d(A-T)]·聚[d(A-T)]（I）、聚[d(G-C)]·聚[d(G-C)]（II）、聚[d(A-C)]·聚[d(G-T)]（III）以及同聚核苷酸：聚(dA)·聚(dt)（IV）、聚(dG)·聚(dC)（V），还有大肠杆菌DNA中，水与嘌呤残基的C8H基团之间1H----3H交换的速率常数。在这些条件下观察到的交换延迟（与B型DNA相比）与（I）的B型交替结构模型相符，并且归因于溶液中（V）存在B型和A型构象异构体。（II）、（III）和（IV）中嘌呤残基的交换速率常数与B型DNA相比没有明显差异，这表明这些多核苷酸在溶液中的构象类似于“经典”B型DNA，并且与针对（IV）提出的“异源”DNA模型不相关。
