Gopanenko Alexander V, Malygin Alexey A, Karpova Galina G
Institute of Chemical Biology and Fundamental Medicine SB RAS, Novosibirsk 630090, Russia; Novosibirsk State University, Novosibirsk 630090, Russia.
Institute of Chemical Biology and Fundamental Medicine SB RAS, Novosibirsk 630090, Russia; Novosibirsk State University, Novosibirsk 630090, Russia.
Biochim Biophys Acta. 2015 Feb;1854(2):101-9. doi: 10.1016/j.bbapap.2014.11.001. Epub 2014 Nov 8.
Association of ribosomal proteins with rRNA during assembly of ribosomal subunits is an intricate process, which is strictly regulated in vivo. As for the assembly in vitro, it was reported so far only for prokaryotic subunits. Bacterial ribosomal proteins are capable of selective binding to 16S rRNA as well as to its separate morphological domains. In this work, we explored binding of total protein of human 40S ribosomal subunit to the RNA transcript corresponding to the major 3'-domain of 18S rRNA. We showed that the resulting ribonucleoprotein particles contained almost all of the expected ribosomal proteins, whose binding sites are located in this 18S rRNA domain in the 40S subunit, together with several nonspecific proteins. The binding in solution was accompanied with aggregation of the RNA-protein complexes. Ribosomal proteins bound to the RNA transcript protected from chemical modification mostly those 18S rRNA nucleotides that are known to be involved in binding with the proteins in the 40S subunit and thereby demonstrated their ability to selectively bind to the rRNA in vitro. The possible implication of unstructured extensions of eukaryotic ribosomal proteins in their nonspecific binding with rRNA and in subsequent aggregation of the resulting complexes is discussed.
核糖体亚基组装过程中核糖体蛋白与rRNA的结合是一个复杂的过程，在体内受到严格调控。至于体外组装，目前仅报道了原核亚基的情况。细菌核糖体蛋白能够选择性地结合到16S rRNA及其单独的形态结构域上。在这项工作中，我们研究了人40S核糖体亚基的总蛋白与对应于18S rRNA主要3'结构域的RNA转录本的结合。我们发现，所得的核糖核蛋白颗粒几乎包含了所有预期的核糖体蛋白，其结合位点位于40S亚基的这个18S rRNA结构域中，同时还包含几种非特异性蛋白。溶液中的结合伴随着RNA-蛋白复合物的聚集。与RNA转录本结合的核糖体蛋白主要保护那些已知参与40S亚基中与蛋白结合的18S rRNA核苷酸免受化学修饰，从而证明了它们在体外选择性结合rRNA的能力。本文讨论了真核核糖体蛋白的无结构延伸在其与rRNA的非特异性结合以及所得复合物随后聚集过程中的可能作用。
