title: Photo-induced labelling of Escherichia coli ribosomes by a tobramycin analog.
abstract: An [3H]azidobenzyl derivative of tobramycin, a 4,6-disubstituted 2-deoxystreptamine aminoglycoside, has been synthesized, and its ability to label Escherichia coli 70-S ribosomes under photoactivation has been studied. Two concentrations of the photolabel, corresponding to the saturation of the two classes of tobramycin sites on the ribosomes, were used. The results show that, at high antibiotic concentrations which induce maximal misreading during protein synthesis, most of the ribosomal proteins are labelled. At low antibiotic concentration, which results in the saturation of the first-class sites, a few proteins of both subunits are labelled, including L6, S4, S5, and, to a lesser extent, L2, L13 and S18. The 30-S subunit is, on the whole, labelled more efficiently than the 50-S subunit.
mesh_terms: D000345:Affinity Labels; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001386:Azides; D001426:Bacterial Proteins / Q000096:biosynthesis; D001665:Binding Sites / Q000187:drug effects; D004926:Escherichia coli / Q000187:drug effects* / Q000378:metabolism / Q000528:radiation effects; D007553:Isotope Labeling; D012269:Ribosomal Proteins / Q000096:biosynthesis; D012270:Ribosomes / Q000187:drug effects* / Q000528:radiation effects; D014031:Tobramycin / Q000031:analogs & derivatives / Q000494:pharmacology*; D014316:Tritium
chemical_list: D000345:Affinity Labels; D000900:Anti-Bacterial Agents; D001386:Azides; D001426:Bacterial Proteins; D012269:Ribosomal Proteins; D014316:Tritium; C037947:6'-N-4-azidobenzyltobramycin; D014031:Tobramycin