Gentamicin is an aminoglycoside drug that acts on ribosomes in bacteria, inhibits bacterial protein synthesis, and destroys the integrity of bacterial cell membranes. This drug can first pass through the outer membrane porin through passive diffusion, and then enter the cell through the cell membrane through the transport system, and irreversibly bind to the 30s subunit of the isolated ribosome, leading to the destruction of the A position, and further: (1) prevent the correct positioning of aminoacyl tRNA at the A position, especially the binding of methylthionyl tRNA, thus interfering with the assembly of functional ribosomes and inhibiting the formation of the 70s initiating complex. (2) Induce tRNA and mRNA code triad mismatch, cause 30s subunit of complete ribosome to misread the genetic code, cause wrong amino acid to insert into protein structure, and lead to abnormal and non functional protein synthesis. (3) It prevents the termination factor from binding to the A position, so that the synthesized peptide chain cannot be released, and prevents the complete ribosome from dissociating for 70s. (4) It hinders the depolymerization and assembly of polyribosomes, resulting in the depletion of ribosomes in bacteria.
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