Growing cultures of mutant Escherichia coli with temperature-senstive peptidyl-tRNA hydrolase were shifted to nonpermissive 4o degrees. There followed a roughly linear increase in a fraction of isolated tRNA (over 50% after 20 min) whose amino acid-accepting activity was masked until treatment with active peptidyl-tRNA hydrolase. The ionophoretic mobility of amino acid label associated with thi...

Expression of the tryptophanase (tna) operon of Escherichia coli is regulated by catabolite repression and tryptophan-induced transcription antitermination. In a previous study, we reproduced the regulatory features of this operon observed in vivo by using an in vitro S-30 system. We also found that, under inducing conditions, the leader peptidyl-tRNA (TnaC-peptidyl-tRNA(Pro)) is not cleaved; i...

At nonpermissive temperatures the peptidyl-tRNA hydrolase of pth(Ts) bacterial mutants is inactivated, and cells accumulate peptidyl-tRNA and die. Doses of erythromycin, lincomycin, or clindamycin that inhibited the growth of antibiotic-hypersensitive DB-11 pth+ cells accelerated the killing of DB-11 pth(Ts) cells at nonpermissive temperatures. Erythromycin and lincomycin also stimulated the ac...

Half the ribosomes translating the mRNA for phage T4 gene 60 topoisomerase subunit bypass a 50 nucleotide coding gap between codons 46 and 47. The pairing of codon 46 with its cognate peptidyl-tRNA anticodon dissociates, and following mRNA slippage, peptidyl-tRNA re-pairs to mRNA at a matched triplet 5' adjacent to codon 47, where translation resumes. Here, in studies with gene 60 cassettes, it...

Peptidyl-tRNA hydrolase (Pth) releases tRNA from peptidyl-tRNA by cleaving the ester bond between the peptide and the tRNA. Genetic analyses using Escherichia coli harbouring temperature-sensitive Pth have identified a number of translation factors involved in peptidyl-tRNA release. Accumulation of peptidyl-tRNA in the cells leads to depletion of aminoacyl-tRNA pools and halts protein biosynthe...

The macrolide-lincosamide-streptogramin B class (MLS) of antibiotics contains structurally different but functionally similar drugs, that all bind to the 50S ribosomal subunit. It has been suggested that these compounds block the path by which nascent peptides exit the ribosome. We have studied the mechanisms of action of four macrolides (erythromycin, josamycin, spiramycin and telithromycin), ...

Peptidyl-tRNA hydrolase activity from Escherichia coli ensures the recycling of peptidyl-tRNAs produced through abortion of translation. This activity, which is essential for cell viability, is carried out by a monomeric protein of 193 residues. The structure of crystalline peptidyl-tRNA hydrolase could be solved at 1.2 A resolution. It indicates a single alpha/beta globular domain built around...

Peptidyl-tRNA dissociation from ribosomes is an energetically costly but apparently inevitable process that accompanies normal protein synthesis. The drop-off products of these events are hydrolysed by peptidyl-tRNA hydrolase. Mutant selections have been made to identify genes involved in the drop-off of peptidyl-tRNA, using a thermosensitive peptidyl-tRNA hydrolase mutant in Escherichia coli. ...

We report on the first synthesis, kinetic evaluation and application of novel substrate-derived inhibitors against the Staphylococcus aureus cysteine protease-transpeptidase, sortase (staphylococcal surface protein sorting A, SrtA). The peptidyl-diazomethane and peptidyl-chloromethane analogues, Cbz (benzyloxycarbonyl)-Leu-Pro-Ala-Thr-CHN(2) (I) and Cbz-Leu-Pro-Ala-Thr-CH(2)Cl (II) respectively...

The ribosome catalyzes peptide bond formation between peptidyl-tRNA in the P site and aminoacyl-tRNA in the A site. Here, we show that the nature of the C-terminal amino acid residue in the P-site peptidyl-tRNA strongly affects the rate of peptidyl transfer. Depending on the C-terminal amino acid of the peptidyl-tRNA, the rate of reaction with the small A-site substrate puromycin varied between...