Direct determination of the properties of peptide transport systems in Escherichia coli, using a fluorescent-labeling procedure

Abstract

A direct study of peptide uptake by Escherichia coli was made using a fluorescent procedure. After incubation with the bacteria, peptides remaining in the medium were dansylated, separated chromatographically, and quantitated from their fluorescent intensities and/or from their incorporated radioactivity when tritiated dansyl derivatives were prepared. Peptide uptake was apparently not regulated and proceeded continuously until complete, with the absorbed peptides undergoing rapid intracellular hydrolysis and the excess amino acid residues leaving the cell. Thus, peptide uptake and amino acid exodus occur concurrently. However, peptidase-resistant substrates, e.g. triornithine and glycylsarcosine, which can be similarly estimated in cell extracts, were accumulated about 1,000-fold. The influence of amino acid composition and chain length on rates of transport was assessed. Different strains of E. coli showed variability in their rates of di-and oligopeptide transport. With respect to energy coupling, both the diand oligopeptide permeases behaved like shock-sensitive transport systems.

A new type of transporter with a new type of cellular function: l‐lysine export from Corynebacterium glutamicum

“…In contrast, the necessity of possessing such an exporter could also be of relevance for bacteria in general. The formation of amino acid constituents derived from peptides has been noted with E. coli (Payne and Bell, 1979;Payne and Smith, 1994) and Streptococcus faecalis (Nisbet and Payne, 1982). In the case of C. glutamicum the peptide-derived export of L-lysine has been used to study relevant export characteristics (Erdmann et al, 1993).…”

The ami locus of the Gram‐positive bacterium Streptococcus pneumoniae is similar to binding protein‐dependent transport operons of Gram‐negative bacteria

“…Secondary effects of mutations affecting oligopeptide transport could be mediated through changes in amino acid transport systems. Indeed, peptide transport could be accompanied in wild-type S. pneumoniae, as in E. coli (Payne and Bell, 1979), by efflux of those amino acids whose internal pools are increased as a consequence of unregulated peptide uptake. Efflux through ion-driven amino acid transport systems could contribute to the establishment of a proton-motive force.…”

Crystal structure of the dipeptide binding protein from Escherichia coli involved in active transport and chemotaxis

“…The dipeptide permease transports dipeptides across the Escherichia coli cytoplasmic membrane with high affinity, allowing a wide variety of dipeptides to enter (Payne & Bell, 1979;Perry & Gilvarg, 1984). Dipeptides as structurally and chemically diverse as glycyl-glycine, lysyl-lysine, and phenylalanylphenylalanine are taken up at about the same rates (Payne & Bell, 1979). A 57-kDa periplasmic binding protein, the product of the dppA gene, acts as the initial receptor for dipeptides during their uptake through this system.…”