Poly(dA-dT).poly(dA-dT) in low salt appears to be a left-handed B-helix combined use of chemical theory, fiber diffraction and NMR spectroscopy.
Poly(dA-dT).poly(dA-dT) in low salt appears to be a left-handed B-helix combined use of chemical theory, fiber diffraction and NMR spectroscopy.
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结合化学理论、纤维衍射和核磁共振波谱，低盐中的聚(dA-dT).聚(dA-dT)似乎是左手B螺旋。
DOI：
10.1080/07391102.1983.10507450
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发表时间：
1983
影响因子：
4.4
通讯作者：
Sasisekharan,V
中科院分区：
文献类型：
--
作者：
Gupta,G;Sarma,MH;Dhingra,MM;Sarma,RH;Rajagopalan,M;Sasisekharan,V
聚（dA-dT）•聚（dA-dT）在纤维状态下可以采用B-和D-两种形态。理论能量计算和纤维衍射分析表明，聚（dA-dT）•聚（dA-dT）在这两种形式中可以有三种结构模型，即右旋和左旋沃森克里克模型和左旋hoogsteen模型，总共有六种可能的模型。B型或d型聚合物的纤维数据或能量计算无法区分任何一种模型。然而，将质子化学位移与理论计算的质子化学位移进行比较，以及对可交换和不可交换质子的NOE研究表明，聚（dA-dT）•聚（dA-dT）在低盐溶液中主要以左旋b构象存在。
Poly(dA-dT)•poly(dA-dT) can adopt the B- and D- forms in the fibrous state. Theoretical energy calculations and fiber diffraction analyses suggest that there can be three structural models of poly(dA-dT)•poly(dA-dT) in each of these two forms viz right and left-handed Watson Crick models and left-handed Hoogsteen—a total of six possible models. Fiber data for the polymer in the B- or the D-form or energy calculations cannot distinguish any one model from the other. However, a comparison of observed proton chemical shifts with the theoretically computed ones and the NOE studies on exchangeable and nonexchangeable protons suggest that poly(dA-dT)•poly(dA-dT) in low salt solution exists predominantly in the left-handed B-conformation.