Structural and functional study of translation apparatus from the viewpoint of molecular mimicry and prion transmission

最近的分子和结构研究，包括来自这个实验室的研究，揭示了被称为翻译因子的蛋白质模仿tRNA的形状。其中一种是多肽释放因子（RF），它编码一种三肽，该三肽作为“反密码子”来破译mRNA中的停止密码子。这些发现让我们提出了蛋白质和RNA之间大分子模仿的新概念。此外，出芽酵母的[PSI^+]元件代表翻译释放因子eRF3在细胞质中繁殖和传递的朊病毒构象。在许多层面上，酵母朊病毒类似于哺乳动物朊病毒，人们的兴趣在于了解朊病毒如何能够在等基因菌株中产生变异。我们从分子模拟和朊病毒传播的角度对RRF和核糖体循环因子（RRF）进行了研究，发现了以下几个方面。1) S. Pombe erf的晶体结构和功能域注释3.2)EF-G和RRF在更多tRNA-mimicry结构域的功能相互作用。3)普遍保守的23S rRNA的A2602对肽释放活性的关键作用。4)酵母eRF3的部分朊病毒结构域掩盖了eRF3在eRF1.5中的结合位点)核糖体蛋白L11结构域与RF1和RF2的协同相互作用，负责翻译终止。6)酵母eRF3的非朊病毒状态n端结构域对eRF3.7) RRF的功能和稳定性的作用（不依赖EF-G的核糖体转位酶活性）。8)发现一种独立于Hsp104.9的新型[PSI^+]朊病毒变体。在传播到Sup35朊病毒变体期间，在弱到强或强到弱[PSI^+]转换中保留了构象记忆。10)酿酒链球菌Sup35的n端41-残基结构域是[PSI^+]朊病毒传播的种间屏障决定因素。11)酵母朊病毒维持相关因子的全基因组筛选和遗传选择，包括Hsp104和其他新成分。少

Recent molecular and structural studies including those from this laboratory have revealed that proteins called translation factors mimic the shape of tRNA. One of them, a polypeptide release factor (RF), encodes a tripeptide that serves as an ‘anticodon' to decipher stop codons in mRNA. These findings let us to propose the novel concept of macromolecular mimicry between protein and RNA. Moreover, The [PSI^+] element of budding yeast represents the prion conformation of translation release factor eRF3 that is propagated and transmitted in the cytoplasm. On many levels, yeast prions are analogous to mammalian prions and much interest lies in understanding how prions are able to generate variation in isogenic strains. We have investigated RFs and ribosome-recycling-factor (RRF) from the viewpoint of molecular mimicry and prion transmission, and uncovered the following aspects.1) Crystal structure and functional domain annotation of S. Pombe eRF3.2) Functional interplay of EF-G and RRF at … More their tRNA-mimicry domains.3) The critical role of the universally conserved A2602 of 23S rRNA for the peptide-release activity.4) Part of the prion domain of yeast eRF3 masks the eRF3-binding site in eRF1.5) The role of ribosomal protein L11 domains for the cooperative interaction with RF1 and RF2, responsible for translation termination.6) The role of nonprion-state N-terminal domain of yeast eRF3 for functionality and stability of eRF3.7) RRF disassembles the posttermination ribosomal complex independent of the ribosomal translocase activity of EF-G.8) Discovery of a novel [PSI^+] prion variant that is independent of Hsp104.9) Conformational memory preserved in a weak-to-strong or strong-to-weak [PSI^+] conversion during transmission to Sup35 prion variants.10) The N-terminal 41-residue domain of S. cerevisiae Sup35 is a species-barrier determinant for [PSI^+] prion transmission.11) Genome-wide screening and genetic selection for factors, including Hsp104 and other novel components, responsible for the maintenance of yeast prions. Less