Structural basis of early translocation events on the ribosome

Article

关键词: ELONGATION-FACTOR G;    TRANSFER-RNA;    EF-G;    HYBRID STATE;    CRYSTAL-STRUCTURE;    ESCHERICHIA-COLI;    TRANSLATION;    DYNAMICS;    GTP;    SELECTION;   

DOI  :  10.1038/s41586-021-03713-x

来源: SCIE

【 摘 要 】

Peptide-chain elongation during protein synthesis entails sequential aminoacyl-tRNA selection and translocation reactions that proceed rapidly (2-20 per second) and with a low error rate (around 10(-3) to 10(-5) at each step) over thousands of cycles(1). The cadence and fidelity of ribosome transit through mRNA templates in discrete codon increments is a paradigm for movement in biological systems that must hold for diverse mRNA and tRNA substrates across domains of life. Here we use single-molecule fluorescence methods to guide the capture of structures of early translocation events on the bacterial ribosome. Our findings reveal that the bacterial GTPase elongation factor G specifically engages spontaneously achieved ribosome conformations while in an active, GTP-bound conformation to unlock and initiate peptidyl-tRNA translocation. These findings suggest that processes intrinsic to the pre-translocation ribosome complex can regulate the rate of protein synthesis, and that energy expenditure is used later in the translocation mechanism than previously proposed.

【 授权许可】

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