Bhatia Simran S, Weiss Tristen C, Romaniuk Paul J
Department of Biochemistry and Microbiology, University of Victoria, PO Box 3055, Victoria, BC V8W 3P6, Canada.
Biochemistry. 2008 Aug 12;47(32):8398-405. doi: 10.1021/bi800080c. Epub 2008 Jul 18.
Xenopus zinc finger protein p43 binds to 5S RNA in immature oocytes to form a 42S ribonucleoprotein storage particle. To determine the role of individual zinc fingers of the protein in this RNA binding activity, a series of deletion and substitution mutants of p43 were constructed. The effects of the various mutations on the RNA binding activity of p43 were determined using a quantitative equilibrium binding assay. The results indicate that zinc fingers 1 and 4 of p43 are essential for the binding of the protein to 5S RNA. In the case of finger 1, four amino acids key to RNA binding are found on the same face of the alpha-helix, while in the case of finger 4, two key residues are clustered at the start of the alpha-helix. The similarities and differences in the mechanisms by which fingers 1 and 4 of p43 interact with 5S RNA are compared to the interaction of the zinc fingers of Xenopus transcription factor IIIA with 5S RNA.
非洲爪蟾锌指蛋白p43在未成熟卵母细胞中与5S RNA结合，形成一个42S核糖核蛋白储存颗粒。为了确定该蛋白中各个锌指在这种RNA结合活性中的作用，构建了一系列p43的缺失和替换突变体。使用定量平衡结合试验确定了各种突变对p43的RNA结合活性的影响。结果表明，p43的锌指1和锌指4对于该蛋白与5S RNA的结合至关重要。就锌指1而言，RNA结合的四个关键氨基酸位于α螺旋的同一面上，而对于锌指4，两个关键残基聚集在α螺旋的起始处。将p43的锌指1和锌指4与5S RNA相互作用的机制的异同与非洲爪蟾转录因子IIIA的锌指与5S RNA的相互作用进行了比较。
