High-Resolution DNA Dual-Rulers Reveal a New Intermediate State in Ribosomal Frameshifting

Allosteric Effects of EF-G Domain I Mutations Inducing Ribosome Frameshifting Revealed by Multiplexed Force Spectroscopy

Ribosome translocation catalyzed by elongation factor G (EF-G) is a critical step in protein synthesis where the ribosome typically moves along the mRNA by three nucleotides at each step. To investigate the mechanism of EF-G catalysis, it is essential to precisely resolve the ribosome motion at both ends of the mRNA, which, to our best knowledge, is only achieved with the magnetic-based force spectroscopy developed by our groups. Here, we introduce a novel multiplexed force spectroscopy technique that, for the first time, offers single-nucleotide resolution for multiple samples. This technique combines multiple acoustic force generators with the smallest atomic magnetometer designed for biological research. Utilizing this technique, we demonstrate that mutating EF-G at the GTP binding pocket results in the ribosome moving only two nucleotides on both ends of the mRNA, thereby compromising ribosome translocation. This finding suggests a direct link between GTP hydrolysis and ribosome translocation. Our results not only provide mechanistic insights into the role of GTP binding pocket but also illuminate how allosteric mutations can manipulate translocation. We anticipate broader applications of our technique in the ribosome field, leveraging its high efficiency and single-nucleotide resolution.

Advances in the Biological Application of Force-Induced Remnant Magnetization Spectroscopy

Biomolecules participate in various physiological and pathological processes through intermolecular interactions generally driven by non-covalent forces. In the present review, the force-induced remnant magnetization spectroscopy (FIRMS) is described and illustrated as a novel method to measure non-covalent forces. During the FIRMS measurement, the molecular magnetic probes are magnetized to produce an overall magnetization signal. The dissociation under the interference of external force yields a decrease in the magnetic signal, which is recorded and collected by atomic magnetometer in a spectrum to study the biological interactions. Furthermore, the recent FIRMS development with various external mechanical forces and magnetic probes is summarized.

Twice exploration of tRNA +1 frameshifting in an elongation cycle of protein synthesis

Inducing tRNA +1 frameshifting to read a quadruplet codon has the potential to incorporate a non-natural amino acid into the polypeptide chain. While this strategy is being considered for genome expansion in biotechnology and bioengineering endeavors, a major limitation is a lack of understanding of where the shift occurs in an elongation cycle of protein synthesis. Here, we use the high-efficiency +1-frameshifting SufB2 tRNA, containing an extra nucleotide in the anticodon loop, to address this question. Physical and kinetic measurements of the ribosome reading frame of SufB2 identify twice exploration of +1 frameshifting in one elongation cycle, with the major fraction making the shift during translocation from the aminoacyl-tRNA binding (A) site to the peptidyl-tRNA binding (P) site and the remaining fraction making the shift within the P site upon occupancy of the A site in the +1-frame. We demonstrate that the twice exploration of +1 frameshifting occurs during active protein synthesis and that each exploration is consistent with ribosomal conformational dynamics that permits changes of the reading frame. This work indicates that the ribosome itself is a determinant of changes of the reading frame and reveals a mechanistic parallel of +1 frameshifting with -1 frameshifting.