Binding specificity of the periplasmic oligopeptide-binding protein from Escherichia coli

Abstract

The structural properties required for the binding of peptide substrates to the Escherichia coli periplasmic protein involved in oligopeptide transport were surveyed by measuring the ability of different peptides to compete for binding in an equilibrium dialysis assay with the tripeptide Ala-Phe-[3H]Gly. The protein specifically bound oligopeptides and failed to bind amino acids or dipeptides. Acetylation of the peptide amino terminus of (Ala)3 severely impaired binding, whereas esterification of the carboxyl terminus significantly reduced but did not completely eliminate binding. Peptides composed of L-amino acids competed more effectively than did peptides containing D-residues or glycine. Experiments with a series of alanyl peptide homologs demonstrated a decrease in competitive ability with increasing chain length beyond tripeptide. Competition studies with tripeptide homologs indicated that a wide variety of amino acyl side chains were tolerated by the periplasmic protein, but side-chain composition did affect binding. Fluorescence emission data suggested that this periplasmic protein possesses more than one substrate-binding site capable of distinguishing peptides on the basis of amino acyl side chains.

Peptide uptake by Salmonella typhimurium The periplasmic oligopeptide‐binding protein

“…This has not previously been formally demonstrated. However an abundant periplasmic protein from E. coli has recently been identified by its ability to bind peptides [18]. In this paper we show that this periplasmic peptide-binding protein is identical with the OppA protein.…”

“…Like other periplasmic binding proteins, the OppA protein has high affinity for its sub- 18,311). In this paper we describe the purification and characterization of the OppA protein.…”

“…Thus, neither the Dpp binding protein nor any other periplasmic binding protein shows significant immunological similarity to OPPA. A periplasmic peptide-binding protein has recently been purified from E. coli [18]. As this protein has a similar molecular mass to OppA and as its binding specificity is similar to that for transport via Opp, it seemed likely that this protein was OppA.…”

Poly(A)+ RNA from sheep omasal epithelium induces expression of a peptide transport protein(s) in Xenopus laevis oocytes.

“…It has been shown that blocking either the amino or carboxyl terminal group could reduce transport affinity and lipophilic side-chains could increase uptake affinity (Guyer et al, 1986). Peptides with α-amino groups have higher affinity than peptides with β-amino groups.…”

Modelagem molecular das proteínas captadoras de molibdato (ModA) e oligopeptídeos (OppA) de Xanthomonas axonopodis pv. citri .

“…A capacidade de captar peptídeos torna-se, portanto, uma propriedade essencial para a sobrevivência das bactérias em diferentes ambientes, bióticos e abióticos (PAYNE e GILBARG, 1968;HILLES e HIGGINS, 1986). Em bactérias, a captação de peptídeos é feita por meio de três sistemas de transporte principais que foram detalhadamente estudados em Salmonella typhimurium (Stm) e Eco (GUYER et al, 1985;HILLES e HIGGINS, 1986). Nessas bactérias três sistemas de transporte do tipo ABC se encarregam da captação de peptídeos, a saber: (i) um sistema específico de captação de dipeptídeos, denominado dipeptide permease (Dpp); (ii) um sistema de captação de tripeptídeos, denominado tripeptide permease (Tpp); (iii) e um sistema de captação de oligopeptídeos, ou oligopeptídeo permease (Opp).…”