DNA BENDING BY ASYMMETRIC PHOSPHATE NEUTRALIZATION
DNA BENDING BY ASYMMETRIC PHOSPHATE NEUTRALIZATION
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DOI：
10.1126/science.7997878
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发表时间：
1994-12-16
期刊：
影响因子：
56.9
通讯作者：
MAHER, LJ
中科院分区：
文献类型：
--
作者：
STRAUSS, JK;MAHER, LJ
当DNA与蛋白质络合时，往往会弯曲。了解导致DNA弯曲的作用力对于探索这些大分子之间的相互作用具有基本价值。人们设计了一系列实验来验证这一假设，即具有阳离子表面的蛋白质可以通过中和DNA表面的磷酸盐来诱导DNA大幅弯曲。据预测，剩余阴离子螺旋中的磷酸盐之间的排斥力会导致不平衡的压缩力，从而使DNA朝着蛋白质变形。这一假说得到了电泳实验的结果的支持，在这些实验中，当一个螺旋面被加入中性磷酸类似物部分修饰时，DNA会自发弯曲。相对于固有DNA曲率位置(六脱氧腺苷酸束)的相位可以估计静电弯曲角度，并证明这种修饰的DNA如预测的那样朝着中和表面变形。类似的模型系统可能有助于探索磷酸中和在多大程度上可以解释特定蛋白质造成的DNA弯曲。
DNA is often bent when complexed with proteins. Understanding the forces responsible for DNA bending would be of fundamental Value in exploring the interplay of these macromolecules. A series of experiments was devised to test the hypothesis that proteins with cationic surfaces can induce substantial DNA bending by neutralizing phosphates on one DNA face. Repulsions between phosphates in the remaining anionic helix are predicted to result in an unbalanced compression force acting to deform the DNA toward the protein. This hypothesis is supported by the results of electrophoretic experiments in which DNA spontaneously bends when one helical face is partially modified by incorporation of neutral phosphate analogs. Phasing with respect to a site of intrinsic DNA curvature (hexadeoxyadenylate tract) permits estimation of the electrostatic bend angle, and demonstrates that such modified DNAs are deformed toward the neutralized surface, as predicted. Similar model systems may be useful in exploring the extent to which phosphate neutralization can account for DNA bending by particular proteins.