Versatality of Nucleic Acid Structure and its recognition

核酸结构的多样性及其识别

• 批准号: 61303019
• 负责人: SHINDO Heisaburo
• 金额: $ 3.14万
• 依托单位: Tokyo College of Pharmacy
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Co-operative Research (A)
• 财政年份: 1986
• 资助国家: 日本
• 起止时间: 1986 至 1987
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-61303019/
• 关键词: Structures of DNA; Structure and function of tRNA; HU protein; cro repressor; Structure of hairpin loop; Structure of bulge loop; Dynamics of DNA; NMR; CD; DNA; tRNA; 制限酵素; ヘアピンループ; Croリプレッサー; Hu-DNA複合体

(i) Versatality of the Structure of OligoDNAs. Four different structures characterized by sugar prosphate conformations were demonstrated by ramann spectroscopy, and they were designated as Bn form specific to GC, Bh form to GG, Bn form to AT and B' form to AA sequences. Furthermore, cleavaga pattern of restriction enzymes were reasonably interpreted in terms of structural rigidity of diad sequences, i.e., the most rigid structural unit such as CA was hardly cleaved,whereas soft structural unit such as CT was often an attacked site by the enzymes.(2) Hairpin and Bulge Loop Structures. Loop structures were found to be unexpectedly stablized by base stacking interactions. The stability of hairpin loop was maximum when loop length n=1-3, while the stability of bulge loop monotoneously decreased as an increasing loop length.(3) Versatality of tRNA and its Interaction with Aminoacylase. tRNA _<minor>^<Ile> which codes Ile was sequenced, and the first letter of its anticodon was found to be new nucleotide, lysidylcytidine named as lysidine. In the gene of this tRNA the first letter of the anticodon was C but the modified cytidine in the mature tRNA recognized A. Interesting relations between higher structure of tRNA and its function were obtained by means of acceptability of amino acids by modification of anticodon bases.(4) DNA-Protein Complexes. Single crystal structure of HU-DNA were solved at 3.5 A resolution,and interacting modes of HU-HU and unique orientation of bound oligo octamers in the crystal unit were clarified. As for cro-DNA complex the binding modes and its strength were measured by NMR and CD as a function of base sequence of base sequence of bound DNA, as the reslts concluded that only the consensus sequence for the operator induced the structural changes in both cro protein and DNA itself by complex formation.

(i)寡聚DNA结构的多样性。拉曼光谱显示了四种不同的糖链构象，分别为GC特有的Bn型、GG特有的Bh型、AT特有的Bn型和AA特有的B'型。此外，根据二联体序列的结构刚性合理地解释了限制性内切酶的裂解模式，即，最硬的结构单元如CA几乎不被切割，而软的结构单元如CT通常是酶的攻击位点。(2)发夹和凸起环结构。发现环结构通过碱基堆积相互作用意外地稳定。发夹环的稳定性在环长n=1-3时最高，而隆突环的稳定性随环长的增加而单调下降。(3)tRNA的多功能性及其与氨基酰化酶的相互作用。对<minor><Ile>编码Ile的tRNA_1进行了测序，发现其反密码子的第一个字母为新的核苷酸，即赖氨酸基胞苷，命名为lysidine。在该tRNA基因中，反密码子的第一个字母是C，而成熟tRNA中的修饰胞苷识别A。通过对反密码子碱基的修饰，获得了tRNA高级结构与其功能之间的有趣关系。(4)DNA-蛋白质复合物。在3.5A分辨率下解析了HU-DNA的单晶结构，阐明了HU-HU的相互作用模式和结合寡聚体在晶体单元中的独特取向。对于cro-DNA复合物，用NMR和CD测定了其结合方式和结合强度随结合DNA碱基序列的变化，结果表明，只有操纵子的共有序列才能通过复合物的形成引起cro蛋白和DNA本身的结构变化。

项目成果

S. Fujino et al.: Nucl. Acids Symposium Series. 17. 191-194 (1984)

S. Fujino 等人：Nucl。

Y.Nishimura;C.Torigoe;M.Tsuboi: Nucl.Acids Res.14. 2737-2748 (1986)

Y.Nishimura；C.Torigoe；M.Tsuboi：核酸研究 14。

H.Shindo et al.: Bull. Chem. Soc. Jpn.60. 1631-1640 (1987)

H.Shindo 等人：公牛。

D.Kohsa et al.: Biochmeistry. 26. 6531-6538 (1987)

D.Kohsa 等人：生物化学。

S. Roy, S. Weinstein, B. Borah, J. Nickol, H. Shindo and J. S. Cohen: "Mechanism of oligonucleotide Formation in Solution" Biochemistry, 25, 7417-7423(1986).

S. Roy、S. Weinstein、B. Borah、J. Nickol、H. Shindo 和 J. S. Cohen：“溶液中寡核苷酸形成的机制”生物化学，25, 7417-7423(1986)。