The Molecular Recognition Mechanism of Nucleic Acid Structure by Beta-Turn Motif of Protein

迄今为止，DNA碱基序列有四种不同的识别基序，分别是蛋白质、螺旋-转-螺旋、β -薄片、锌指和亮氨酸拉链。由Suzuki M.，一种相当新的模式在海胆生精组蛋白预期。H1和H2B。dna结合臂由Ser-Pro-Lys (Arg)-Lys （Arg）残基的重复序列组成。从氨基酸序列上看，该区域可能采用β -turn结构，从而提供了新的识别机制。x射线结构分析在原子水平上确定了这种复合体的分子结构。(1)化学合成了包含该串联氨基酸序列的4个寡肽片段，它们分别对应于颌舌鱼H1的n端区域。本文还合成了几个在分子中心有腺嘌呤（-酪胺）迹的寡核苷酸。用这些化合物进行了几种络合物的结晶，但迄今为止还没有获得适合x射线分析的晶体。对溶液中复杂地层的一系列研究是必要的。(2)利用核磁共振波谱和计算机图形系统确定了抗生素色霉素与DNA寡聚物的复合结构。该模型提供了药物对DNA碱基序列的识别机制，这是一种非常新颖的基序，广泛存在的疏水表面相互作用。(3)开发了计算和绘制dna -蛋白质复合物结构参数的计算机程序，该程序适合于描述复杂相互作用。

To date there are four different recognition motifs of DNA base sequence by protein, helix-turn-helix, beta-sheet, Zn-finger and leucin zipper. By Suzuki M., a quite new mode is expected in sea urchin spermatogenic histones. H1 and H2B. The DNA-binding arms are composed of repeats of Ser-Pro-Lys (Arg)-Lys (Arg) residues. From amino acid sequence, this region may adopt the beta-turn structure, so this offers the novel recognition mechanism. X-ray structure analysis determines the molecular structure at atomic level of this complex formation.(1) Four oligopeptide fragments containing this tandem amino acid sequence were chemically synthe-sized, which correspond to the N-terminal region of H1 of P. angulosus. Several oligonucleotides which have adenine (-tymine) track at the central region in molecule were also chemically synthesized. Several crystallizations of complex by using these compounds have been done, but to date no suitable crystal for X-ray analysis has been obtained. A series of investigations about complex formation in solution are necessary.(2) The complex structure of antibiotic Chromomycin and DNA oligomer was determined based on NMR spectra and computer graphics system. This model offers the recognition mechanism of DNA base sequence by drug which is quite novel motif, a widely spread hydrophobic surface interaction.(3) A computer program of calculating and drawing the structural parameters for DNA-protein complex was developed and is suitable to characterize the complex interaction.