THERMODYNAMICS OF PROTEIN RNA RECOGNITION IN A HIGHLY CONSERVED REGION OF THE LARGE-SUBUNIT RIBOSOMAL-RNA
THERMODYNAMICS OF PROTEIN RNA RECOGNITION IN A HIGHLY CONSERVED REGION OF THE LARGE-SUBUNIT RIBOSOMAL-RNA
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DOI：
10.1021/bi00452a012
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发表时间：
1989-12-26
期刊：
影响因子：
2.9
通讯作者：
DRAPER, DE
中科院分区：
文献类型：
--
作者：
RYAN, PC;DRAPER, DE
来自大肠杆菌的核糖体蛋白L11特异性结合23S核糖体RNA的高度保守区域。通过使用硝化纤维素过滤器结合试验，研究了在这种蛋白质和几种不同的rRNA片段之间形成复合物的热力学。RNA的57个核苷酸区域（C1052-U1108）包含所有蛋白质识别特征，含有该区域的RNA片段与L11的结合比tRNA紧密103-104倍。结合常数约为10 μ。M-1，仅弱依赖于K+浓度（.vdelta）。日志K / .vdelta。log [K+] = -1.4)或温度。结合需要多价阳离子；Mg2+以.apprx的亲和力被吸收到复合物中。3 mm - 1。其他多价阳离子，如Ca2+和Co(NH3)63+，几乎也能促进结合。结合的pH依赖性呈钟形曲线，最大值接近中性pH，但对于测试的两个RNA片段中较小的片段，整个曲线向更高的pH偏移。这一结果表明，较小的片段有利于RNA识别位点的构象稳定的质子化形式，并且可能与该rRNA区域在核糖体周期中经历一系列有序构象变化的假设相关。
Ribosomal protein L11 from Escherichia coli specifically binds to highly conserved region of 23S ribosomal RNA. The thermodynamics of forming a complex between this protein and several different rRNA fragments have been investigated, by use of a nitrocellulose filter binding assay. A 57-nucleotide region of the RNA (C1052-U1108) contains all the protein recognition features, and an RNA fragment containing this region binds L11 103-104-fold more tightly than tRNA. Binding constants are on the order of 10 .mu.M-1 and are only weakly dependent on K+ concentration (.vdelta. log K/.vdelta. log [K+] = -1.4) or temperature. Binding requires multivalent cations; Mg2+ is taken up into the complex with an affinity of .apprx. 3 mM-1. Other multivalent cations tested, Ca2+ and Co(NH3)63+, promote binding nearly as well. The pH dependence of binding is a bell-shaped curve with a maximum near neutral pH, but the entire curves is shifted to higher pH for the smaller of two RNA fragments tested. This result sugests that the smaller fragment favors a conformational stabilizing protonated forms of the RNA recognition site and is potentially relevant to a hypothesis that this rRNA region undergoes an ordered series of conformational changes during the ribosome cycle.