乳糖阻遏蛋白头部片段与一个22碱基对对称乳糖操纵基因之间复合物的氢核磁共振研究。

H NMR study of a complex between the lac repressor headpiece and a 22 base pair symmetric lac operator.

作者信息

Lamerichs R M, Boelens R, van der Marel G A, van Boom J H, Kaptein R, Buck F, Fera B, Rüterjans H

机构信息

Department of Chemistry, University of Utrecht, The Netherlands.

出版信息

Biochemistry. 1989 Apr 4;28(7):2985-91. doi: 10.1021/bi00433a037.

DOI:10.1021/bi00433a037

PMID:2742823

Abstract

A complex between the lac repressor headpiece and a fully symmetric tight-binding 22 bp lac operator was studied by 2D NMR. Several 2D NOE spectra were recorded for the complex in both H2O and 2H2O. Many NOE cross-peaks between the headpiece and DNA could be identified, and changes in the chemical shift of the DNA protons upon complex formation were analyzed. Comparison of these data with those obtained for a complex between the headpiece and a 14 bp half-operator, studied previously [Boelens, R., Scheek, R. M., Lamerichs, R. M. J. N., de Vlieg, J., van Boom, J. H., & Kaptein, R. (1987) in DNA-ligand interactions (Guschlbauer, W., & Saenger, W., Eds.) pp 191-215, Plenum, New York], shows that two headpieces form a specific complex with the 22 bp lac operator in which each headpiece binds in the same way as found for the 14 bp complex. The orientation of the recognition helix in the major groove of DNA in these complexes is opposite with respect to the dyad axis to that found for other repressors.

摘要

通过二维核磁共振研究了乳糖阻遏蛋白头部片段与完全对称的紧密结合型22碱基对乳糖操纵基因之间的复合物。在H₂O和²H₂O中均记录了该复合物的几个二维核欧沃豪斯效应（NOE）谱。可以识别出头部片段与DNA之间的许多NOE交叉峰，并分析了复合物形成时DNA质子化学位移的变化。将这些数据与之前研究的头部片段与14碱基对半操纵基因之间的复合物的数据[Boelens, R., Scheek, R. M., Lamerichs, R. M. J. N., de Vlieg, J., van Boom, J. H., & Kaptein, R. (1987) in DNA-ligand interactions (Guschlbauer, W., & Saenger, W., Eds.) pp 191-215, Plenum, New York]进行比较，结果表明两个头部片段与22碱基对乳糖操纵基因形成了一种特定的复合物，其中每个头部片段的结合方式与14碱基对复合物中的相同。在这些复合物中，识别螺旋在DNA大沟中的取向相对于二分轴与其他阻遏蛋白的相反。