LAC REPRESSOR-OPERATOR INTERACTION .2. EFFECT OF GALACTOSIDES AND OTHER LIGANDS
LAC REPRESSOR-OPERATOR INTERACTION .2. EFFECT OF GALACTOSIDES AND OTHER LIGANDS
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DOI：
10.1016/0022-2836(70)90144-0
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发表时间：
1970-01-01
影响因子：
5.6
通讯作者：
BOURGEOIS, S
中科院分区：
文献类型：
--
作者：
RIGGS, AD;NEWBY, RF;BOURGEOIS, S
用滤膜技术研究了半乳糖苷和其它小分子化合物对纯化的乳糖阻遏蛋白和乳糖操纵蛋白相互作用的影响。在体内作为操纵子诱导剂的化合物被发现在体外抑制阻遏物-操纵子结合。发现阻止体内诱导的化合物在体外抵消诱导剂的作用。这些化合物在体外和体内的作用顺序是相同的，并且与它们对阻遏物的亲和力一致。葡萄糖与阻遏物相互作用，表现为弱的抗诱导物。发现环磷酸腺苷对阻遏物-操纵子结合没有影响。还研究了半乳糖苷对阻遏蛋白-操纵蛋白复合物解离速率的影响。诱导剂异丙基-β-d-硫代半乳糖苷使解离速率增加，而抗诱导剂邻硝基苯基-β-d-岩藻糖苷使解离速率降低。这一结果的影响，无论是在蛋白质的构象变化的变构模型，并在解释bothin vivoandin vitroinduction曲线。
A membrane filter technique was used to study the effect of galactosides and other low molecular weight compounds on the interaction of purifiedlacrepressor andlacoperator. Compounds that functionin vivoas inducers of thelacoperon are found to inhibit repressor-operator bindingin vitro. Compounds that prevent inductionin vivoare found to counteract the effect of inducersin vitro. The order of effectiveness of these compounds is the samein vitroasin vivoand agrees with their affinity for thelacrepressor. Glucose interacts with thelacrepressor and behaves as a weakanti-inducer. Cyclic adenosine monophosphate was found to have no effect on repressor-operator binding. The effect of galactosides on therateof dissociation of repressor-operator complexes was also studied. Therateof dissociation was found to be increased by an inducer, isopropyl-β-d-thiogalactoside, and decreased by an anti-inducer,o-nitrophenyl-β-d-fucoside. This result has implications both in regard to allosteric models for conformational changes in proteins and in regard to the interpretation of bothin vivoandin vitroinduction curves.