作为水合作用和氯化钠含量函数的双螺旋聚（dG-dC）的结构形式、稳定性及转变：一项红外光谱研究
Structural forms, stabilities and transitions in double-helical poly(dG-dC) as a function of hydration and NaCl content. An infrared spectroscopic study.
作者信息
Keller P B, Hartman K A
出版信息
Nucleic Acids Res. 1986 Oct 24;14(20):8167-82. doi: 10.1093/nar/14.20.8167.
The poly(dG-dC) helical duplex forms a modified, B-family structure (B*) at very high hydration and a normal B structure at slightly lower hydration. The B* structure is slightly different in sugar-phosphate and base-stacking conformations than the B structure. Increasing the hydration or decreasing the NaCl content stabilizes B* with respect to B. Poly(dG-dC) forms the Z structure at low NaCl contents when the hydration is sufficiently reduced. At moderate NaCl content, the B to Z transition is sharp and cooperative for hydration with D2O. Hydration with H2O broadens the transition which occurs at lower hydration. This suggests that hydrogen bonding is stronger in the Z structure and helps stabilize Z over B. IR spectra may be used to quantitatively estimate the fractions of B and Z structures present in a sample. Some new indicator bands are described.
聚（dG-dC）螺旋双链在非常高的水合作用下形成一种修饰的B族结构（B*），在水合作用稍低时形成正常的B结构。B结构在糖-磷酸和碱基堆积构象方面与B结构略有不同。增加水合作用或降低NaCl含量相对于B可使B稳定。当水合作用充分降低时，聚（dG-dC）在低NaCl含量下形成Z结构。在中等NaCl含量下，B到Z的转变对于用D2O进行水合作用是尖锐且协同的。用H2O进行水合作用会拓宽在较低水合作用下发生的转变。这表明Z结构中的氢键更强，有助于Z比B更稳定。红外光谱可用于定量估计样品中存在的B和Z结构的比例。描述了一些新的指示带。
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