Nelson H C, Sauer R T
J Mol Biol. 1986 Nov 5;192(1):27-38. doi: 10.1016/0022-2836(86)90461-4.
We have described a set of mutations that alter side-chains on the operator binding surface of lambda repressor. In this paper, we study the interactions of 12 purified mutant repressors with operator and non-operator DNA. The mutant proteins have operator affinities that are reduced from tenfold to greater than 10,000-fold compared to wild-type. Nine of the mutants have affinities for non-operator DNA that are similar to wild-type, two mutants show decreased non-specific binding, and one mutant has increased affinity for non-operator DNA. We discuss these findings in terms of the structural and energetic contributions of side-chain--DNA interactions, and show that certain contacts between the repressor and the operator backbone contribute both energy and specificity to the interaction.
我们已经描述了一组能改变λ阻遏蛋白操纵子结合表面侧链的突变。在本文中，我们研究了12种纯化的突变阻遏蛋白与操纵子DNA和非操纵子DNA的相互作用。与野生型相比，这些突变蛋白对操纵子的亲和力降低了10倍至超过10000倍。其中9种突变体对非操纵子DNA的亲和力与野生型相似，2种突变体显示非特异性结合减少，1种突变体对非操纵子DNA的亲和力增加。我们根据侧链与DNA相互作用的结构和能量贡献来讨论这些发现，并表明阻遏蛋白与操纵子主链之间的某些接触对相互作用的能量和特异性都有贡献。
