Horton N C, Perona J J
Department of Chemistry and Biochemistry and Interdepartmental Program in Biochemistry and Molecular Biology, University of California, Santa Barbara, CA 93106-9510, USA.
Proc Natl Acad Sci U S A. 2000 May 23;97(11):5729-34. doi: 10.1073/pnas.090370797.
Two new high-resolution cocrystal structures of EcoRV endonuclease bound to DNA show that a large variation in DNA-bending angles is sampled in the ground state binary complex. Together with previous structures, these data reveal a contiguous series of protein conformational states delineating a specific trajectory for the induced-fit pathway. Rotation of the DNA-binding domains, together with movements of two symmetry-related helices binding in the minor groove, causes base unstacking at a key base-pair step and propagates structural changes that assemble the active sites. These structures suggest a complex mechanism for DNA bending that depends on forces generated by interacting protein segments, and on selective neutralization of phosphate charges along the inner face of the bent double helix.
两种与DNA结合的EcoRV核酸内切酶的新的高分辨率共晶体结构表明，在基态二元复合物中，DNA弯曲角度存在很大变化。结合之前的结构，这些数据揭示了一系列连续的蛋白质构象状态，描绘了诱导契合途径的特定轨迹。DNA结合结构域的旋转，以及在小沟中结合的两个对称相关螺旋的移动，导致关键碱基对步骤处的碱基解堆叠，并传播组装活性位点的结构变化。这些结构表明了一种复杂的DNA弯曲机制，该机制依赖于相互作用的蛋白质片段产生的力，以及沿着弯曲双螺旋内表面的磷酸盐电荷的选择性中和。
