Kovach J S, Phang J M, Blasi F, Barton R W, Ballesteros-Olmo A, Goldberger R F
J Bacteriol. 1970 Nov;104(2):787-92. doi: 10.1128/jb.104.2.787-792.1970.
Previous studies showed that the enzyme (phosphoribosyltransferase) which catalyzes the first step of the histidine pathway in Salmonella typhimurium plays a role in regulation of the histidine operon. Since histidyl transfer ribonucleic acid (His-tRNA) is required for repression of the histidine operon, we considered the possibility that the role of phosphoribosyltransferase might be realized through an interaction with His-tRNA. One prediction inherent in this idea is that the enzyme should interact with His-tRNA in vitro. Evidence is presented for such an interaction. Binding of (3)H-His-tRNA to purified phosphoribosyltransferase was tested on Sephadex columns and on nitrocellulose filters. The enzyme was found to have a high affinity for tRNA. Comparing the binding of (3)H-His-tRNA with that of tRNA aminoacylated with other (3)H-amino acids disclosed that the binding of the histidyl species of tRNA is favored over that of other species and is dependent upon magnesium-ion concentration.
先前的研究表明,在鼠伤寒沙门氏菌中催化组氨酸途径第一步的酶(磷酸核糖基转移酶)在组氨酸操纵子的调控中发挥作用。由于组氨酸操纵子的阻遏需要组氨酰转移核糖核酸(His - tRNA),我们考虑了磷酸核糖基转移酶的作用可能通过与His - tRNA相互作用来实现的可能性。这个想法中固有的一个预测是,该酶在体外应该与His - tRNA相互作用。本文提供了这种相互作用的证据。在葡聚糖凝胶柱和硝酸纤维素滤膜上测试了³H - His - tRNA与纯化的磷酸核糖基转移酶的结合。发现该酶对tRNA具有高亲和力。将³H - His - tRNA的结合与用其他³H - 氨基酸氨酰化的tRNA的结合进行比较,结果表明tRNA的组氨酰种类的结合比其他种类更受青睐,并且依赖于镁离子浓度。