Department of Chemistry and Biochemistry, Kent State University, 1175 Risman Drive, Kent, OH, 44242, USA.
Department of Physics, Kent State University, 103 Smith Hall, Kent, OH, 44242, USA.
Chembiochem. 2020 Jul 1;21(13):1885-1892. doi: 10.1002/cbic.201900708. Epub 2020 Mar 6.
Ribosomes are ribonucleoprotein particles that are essential for protein biosynthesis in all forms of life. During ribosome biogenesis, transcription, folding, modification, and processing of rRNA are coupled to the assembly of proteins. Various assembly factors are required to synchronize all different processes that occur during ribosome biogenesis. Herein, the RNA chaperone and RNA strand annealing activity of rRNA modification enzyme ribosome small subunit methyltransferase C (RsmC), which modifies guanine to 2-methylguanosine (m G) at position 1207 of 16S rRNA (Escherichia coli nucleotide numbering) located at helix 34 (h34), are reported. A 25-fold increase in the h34 RNA strand annealing rates is observed in the presence of RsmC. Single-molecule FRET experiments confirmed the ability of protein RsmC to denature a non-native structure formed by one of the two h34 strands and to form a native-like duplex. This observed RNA chaperone activity of protein RsmC might play a vital role in the rapid generation of functional ribosomes.
核糖体是核糖核蛋白颗粒，对于所有形式生命的蛋白质生物合成都是必不可少的。在核糖体生物发生过程中，转录、折叠、修饰和 rRNA 的加工与蛋白质的组装偶联。需要各种组装因子来协调核糖体生物发生过程中发生的所有不同过程。在此，报告了 RNA 伴侣和 RNA 链退火活性的 rRNA 修饰酶核糖体小亚基甲基转移酶 C（RsmC），其修饰鸟嘌呤至 16S rRNA 位置 1207 的 2-甲基鸟苷（mG）（大肠杆菌核苷酸编号）位于螺旋 34（h34）。在存在 RsmC 的情况下，h34 RNA 链退火速率增加了 25 倍。单分子 FRET 实验证实了蛋白质 RsmC 使由两个 h34 链之一形成的非天然结构变性并形成类似天然的双链的能力。这种观察到的蛋白质 RsmC 的 RNA 伴侣活性可能在快速生成功能性核糖体中发挥重要作用。
