Wu H N, Kastelic K A, Uhlenbeck O C
University of Colorado, Department of Chemistry and Biochemistry, Boulder 80309-0215.
Nucleic Acids Res. 1988 Jun 10;16(11):5055-66. doi: 10.1093/nar/16.11.5055.
The interaction between the coat protein of the group I bacteriophage fr with its translational operator site is compared with the previously studied R17 interaction. The sequence of the two RNA binding sites differ by 2 of 20 nucleotides and two coat proteins by 17 of 129 amino acids. An analysis of the binding of fr coat protein to 24 operator variants revealed that the two proteins recognize operator sequences in virtually the same way. However, fr coat protein binds to nearly every RNA 6 to 14-fold tighter than R17 coat protein. Since the fr operator is a weaker binding variant and the fr coat protein shows a different temperature dependence of binding, it is unlikely that the two systems have different Kas in vivo. RNA fragments containing the operator sequences can initiate the capsid assembly with both fr and R17 coat protein. Surprisingly, the two coat proteins can form a mixed capsid in vitro.
将I组噬菌体fr的外壳蛋白与其翻译操纵位点之间的相互作用与先前研究的R17相互作用进行了比较。两个RNA结合位点的序列在20个核苷酸中有2个不同，两种外壳蛋白在129个氨基酸中有17个不同。对fr外壳蛋白与24个操纵变体的结合分析表明，这两种蛋白识别操纵序列的方式几乎相同。然而，fr外壳蛋白与几乎每个RNA的结合比R17外壳蛋白紧密6至14倍。由于fr操纵子是一个较弱的结合变体，并且fr外壳蛋白表现出不同的结合温度依赖性，因此这两个系统在体内不太可能具有不同的解离常数。含有操纵序列的RNA片段可以与fr和R17外壳蛋白一起启动衣壳组装。令人惊讶的是，这两种外壳蛋白在体外可以形成混合衣壳。
