Versatality of Nucleic Acid Structure and its recognition

核酸结构的多样性及其识别

基本信息

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

项目摘要

(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）寡头结构的多功能性。拉曼光谱法证明了以糖构构构象为特征的四种不同的结构，并将其指定为特定于gc的bn形式，bh形式为gg，to gg，bn形式为at and b'形式为aa序列。此外，用DIAD序列的结构刚度合理地解释了限制性酶的cleavaga模式，即，诸如CA等最刚性的结构单元（例如CA）几乎没有裂解，而诸如CT之类的软结构单元通常是酶的攻击位点。发现循环结构通过基础堆叠相互作用而意外地稳定了。当循环长度n = 1-3时，发夹环的稳定性是最大的，而凸起环的稳定性单调降低，随着环长度的增加。（3）tRNA的多功能性及其与氨基酰基酶的相互作用。 tRNA _ <minar>^<ile>测序了ile代码，并且发现其反密码子的第一个字母是新的核苷酸，赖氨酸环胞丁胺，称为赖赛丁。在该tRNA的基因中，反密码子的第一个字母是c，但是成熟tRNA中的修饰的胞苷识别A.较高的tRNA结构及其功能之间的有趣关系是通过修饰抗多源碱的可接受性获得的。（4）DNA蛋白质复合物。在3.5 A分辨率下溶液HU-DNA的单晶结构，并阐明了晶体单位中的Hu-Hu的相互作用模式和结合的寡核八聚体的独特方向。至于CRO-DNA复合物，通过NMR和CD来测量结合模式及其强度作为结合DNA的碱基序列的基础序列的函数，因为Reslts得出的结论是，仅操作员的共识序列诱导CRO蛋白和DNA本身的结构变化。