title: Modification of Escherichia coli ribosomes: in vitro termination is less dependent on histidine residues at the peptidyl transferase centre when ribosomes lack protein L11.
abstract: Chemical modification of ribosomes with the histidine specific reagents, 1-fluoro-2,4-dinitrobenzene (FDNB) and diethylpyrocarbonate (DEP), result in a loss of activities in vitro of codon-dependent termination and peptide bond formation. The binding of release factor (RF) to the ribosome is unaffected but the hydrolysis of peptidyl-tRNA is inhibited. On reversal of the modification activity can be restored. Partial protection is provided by chloramphenicol indicating that one or more of the affected residues is at the peptidyl transferase centre. Codon-dependent termination on ribosomes lacking L11, which have a greater affinity for RF-2, is significantly less affected by the modification than on control ribosomes. Peptide bond formation is affected similarly on L11 lacking and normal ribosomes.
mesh_terms: D000217:Acyltransferases / Q000378:metabolism*; D002701:Chloramphenicol / Q000494:pharmacology; D003062:Codon; D004047:Diethyl Pyrocarbonate / Q000494:pharmacology; D004139:Dinitrofluorobenzene / Q000494:pharmacology; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D006639:Histidine / Q000378:metabolism*; D007700:Kinetics; D010443:Peptide Chain Termination, Translational; D010458:Peptidyl Transferases / Q000378:metabolism*; D012269:Ribosomal Proteins / Q000235:genetics*; D012270:Ribosomes / Q000187:drug effects / Q000378:metabolism*
chemical_list: D003062:Codon; D012269:Ribosomal Proteins; C027624:ribosomal protein L11; D006639:Histidine; D002701:Chloramphenicol; D004139:Dinitrofluorobenzene; D000217:Acyltransferases; D010458:Peptidyl Transferases; D004047:Diethyl Pyrocarbonate