Karzai A W, Sauer R T
Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Proc Natl Acad Sci U S A. 2001 Mar 13;98(6):3040-4. doi: 10.1073/pnas.051628298. Epub 2001 Feb 27.
SsrA RNA acts as a tRNA and mRNA to modify proteins whose synthesis on ribosomes has stalled. Such proteins are marked for degradation by addition of peptide tags to their C termini in a reaction mediated by SsrA RNA and SmpB, a specific SsrA-RNA binding protein. Evidence is presented here for the existence of a larger ribonucleoprotein complex that contains ribosomal protein S1, phosphoribosyl pyrophosphate synthase, RNase R, and YfbG in addition to SsrA RNA and SmpB. Biochemical, genetic, and phylogenetic results suggest potential roles for some of these factors in various stages of the ribosome rescue and tagging process and/or the presence of functional interactions between one or more of these proteins and SsrA.
SsrA RNA作为一种转运RNA和信使RNA,对核糖体上合成受阻的蛋白质进行修饰。在由SsrA RNA和SmpB(一种特异性SsrA-RNA结合蛋白)介导的反应中,此类蛋白质通过在其C末端添加肽标签而被标记以便降解。本文提供的证据表明,除了SsrA RNA和SmpB外,还存在一种更大的核糖核蛋白复合体,其包含核糖体蛋白S1、磷酸核糖焦磷酸合成酶、核糖核酸酶R和YfbG。生化、遗传和系统发育结果表明,其中一些因子在核糖体拯救和标记过程的各个阶段可能发挥作用,和/或这些蛋白质中的一种或多种与SsrA之间存在功能相互作用。