Přehled o publikaci

Translation is one of the essential gene regulation machinery that is important for all domains of life. The translation consists of three steps: initiation, elongation and termination, involving a number of translation factors and various types of RNA. During elongation, the anticodon of the transfer RNA (tRNA) is bound to the corresponding codon on the messenger RNA (mRNA), according to the reading frame (RF) of the mRNA, at the ribosomal A site. The correctness of this process can be disrupted during certain conditions, resulting in a shift of the reading frame, also known as frameshifting. We currently know that this phenomenon occurs, but the exact localization of the frameshifting on the ribosome is unknown. Studies have suggested 3 stages of the elongation cycle where this can potentially occur. Here, we focus on the decoding of the mRNA during tRNA accommodation into the A site, with the help of the elongation factor Tu (EF-Tu). To demonstrate whether the shift of the reading frame occurs, we used a biologically derived quadruplet tRNA (qtRNA) that can base-pair with four mRNA bases. We use cryogenic electron microscopy to observe the entire process at near-atomic resolution. Results of the study indicate that there is no frameshift in the reading frame during the decoding of the mRNA by the qtRNA in the A site of the ribosome. méně