Ho P S, Frederick C A, Quigley G J, van der Marel G A, van Boom J H, Wang A H, Rich A
EMBO J. 1985 Dec 16;4(13A):3617-23. doi: 10.1002/j.1460-2075.1985.tb04125.x.
The DNA oligomer d(CGCGTG) crystallizes as a Z-DNA double helix containing two guanine-thymine base pair mismatches of the wobble type. The crystal diffracts to 1 A resolution and the structure has been solved and refined. At this resolution, a large amount of information is revealed about the organization of the water molecules in the lattice generally and more specifically around the wobble base pairs. By comparing this structure with the analogous high resolution structure of d(CGCGCG) we can visualize the structural changes as well as the reorganization of the solvent molecules associated with wobble base pairing. There is only a small distortion of the Z-DNA backbone resulting from introduction of the GT mismatched base pairs. The water molecules cluster around the wobble base pair taking up all of the hydrogen bonding capabilities of the bases due to wobble pairing. These bridging water molecules serve to stabilize the base-base interaction and, thus, may be generally important for base mispairing either in DNA or in RNA molecules.
DNA寡聚物d(CGCGTG)结晶为一种Z-DNA双螺旋结构，其中包含两个摆动型鸟嘌呤-胸腺嘧啶碱基对错配。该晶体的衍射分辨率达到1埃，其结构已得到解析和精修。在这个分辨率下，关于晶格中水分子的总体组织，特别是围绕摆动碱基对的水分子组织，揭示了大量信息。通过将该结构与d(CGCGCG)的类似高分辨率结构进行比较，我们可以直观地看到与摆动碱基配对相关的结构变化以及溶剂分子的重新排列。引入GT错配碱基对导致Z-DNA主链只有很小的扭曲。由于摆动配对，水分子聚集在摆动碱基对周围，占据了碱基的所有氢键结合能力。这些桥连水分子有助于稳定碱基间的相互作用，因此，对于DNA或RNA分子中的碱基错配可能普遍具有重要意义。
