Publications

• Genetic and functional characterization of dpp genes encoding a dipeptide transport system in Lactococcus lactis.

  Sanz Y., Lanfermeijer F.C., Renault P., Bolotin A., Konings W.N., Poolman B.

  The genes encoding a binding-protein-dependent ABC transporter for dipeptides (Dpp) were identified in Lactococcus lactis subsp. cremoris MG1363. Two (dppA and dppP) of the six ORFs (dppAdppPBCDF) encode proteins that are homologous to peptide- and pheromone-binding proteins. The dppP gene contain ... >> More

  The genes encoding a binding-protein-dependent ABC transporter for dipeptides (Dpp) were identified in Lactococcus lactis subsp. cremoris MG1363. Two (dppA and dppP) of the six ORFs (dppAdppPBCDF) encode proteins that are homologous to peptide- and pheromone-binding proteins. The dppP gene contains a chain-terminating nonsense mutation and a frame-shift that may impair its function. The functionality of the dpp genes was proven by the construction of disruption mutants via homologous recombination. The expression of DppA and various other components of the proteolytic system was studied in synthetic and peptide-rich media and by using isogenic peptide-transport mutants that are defective in one or more systems (Opp, DtpT, and/or Dpp). In peptide-rich medium, DppA was maximally expressed in mutants lacking Opp and DtpT. DppA expression also depended on the growth phase and was repressed by tri-leucine and tri-valine. The effect of tri-leucine on DppA expression was abolished when leucine was present in the medium. Importantly, the Dpp system also regulated the expression of other components of the proteolytic system. This regulation was achieved via the internalization of di-valine, which caused a 30-50% inhibition in the expression of the proteinase PrtP and the peptidases PepN and PepC. Similar to the regulation of DppA, the repressing effect was no longer observed when high concentrations of valine were present. The intricate regulation of the components of the proteolytic system by peptides and amino acids is discussed in the light of the new and published data. << Less

  Arch. Microbiol. 175:334-343(2001) [PubMed] [EuropePMC]

• Peptide transport and chemotaxis in Escherichia coli and Salmonella typhimurium: characterization of the dipeptide permease (Dpp) and the dipeptide-binding protein.

  Abouhamad W.N., Manson M., Gibson M.M., Higgins C.F.

  The dipeptide permease (Dpp) is one of three genetically distinct peptide-transport systems in enteric bacteria. Dpp also plays a role in chemotaxis towards peptides. We have devised three selections for dpp mutations based on resistance to toxic peptides (bacilysin, valine-containing peptides, an ... >> More

  The dipeptide permease (Dpp) is one of three genetically distinct peptide-transport systems in enteric bacteria. Dpp also plays a role in chemotaxis towards peptides. We have devised three selections for dpp mutations based on resistance to toxic peptides (bacilysin, valine-containing peptides, and bialaphos). All dpp mutations mapped to a single chromosomal locus between 77 and 78 min in Salmonella typhimurium and at 79.2 min in Escherichia coli. Expression of dpp was constitutive in both species but the absolute level of expression varied widely between strains. At least in part this difference in expression levels is determined by cis-acting sequences. The dpp locus of E. coli was cloned. The first gene in the operon, dppA, encodes a periplasmic dipeptide-binding protein (DBP) required for dipeptide transport and chemotaxis. Downstream of dppA are other genes required for transport but not for chemotaxis. The dipeptide-binding protein was found to share 26.5% sequence identity with the periplasmic oligopeptide-binding protein OppA. << Less

  Mol. Microbiol. 5:1035-1047(1991) [PubMed] [EuropePMC]

• Structure of the nucleotide-binding domain of a dipeptide ABC transporter reveals a novel iron-sulfur cluster-binding domain.

  Li X., Zhuo W., Yu J., Ge J., Gu J., Feng Y., Yang M., Wang L., Wang N.

  Dipeptide permease (Dpp), which belongs to an ABC transport system, imports peptides consisting of two or three L-amino acids from the matrix to the cytoplasm in microbes. Previous studies have indicated that haem competes with dipeptides to bind DppA in vitro and in vivo and that the Dpp system c ... >> More

  Dipeptide permease (Dpp), which belongs to an ABC transport system, imports peptides consisting of two or three L-amino acids from the matrix to the cytoplasm in microbes. Previous studies have indicated that haem competes with dipeptides to bind DppA in vitro and in vivo and that the Dpp system can also translocate haem. Here, the crystal structure of DppD, the nucleotide-binding domain (NBD) of the ABC-type dipeptide/oligopeptide/nickel-transport system from Thermoanaerobacter tengcongensis, bound with ATP, Mg(2+) and a [4Fe-4S] iron-sulfur cluster is reported. The N-terminal domain of DppD shares a similar structural fold with the NBDs of other ABC transporters. Interestingly, the C-terminal domain of DppD contains a [4Fe-4S] cluster. The UV-visible absorbance spectrum of DppD was consistent with the presence of a [4Fe-4S] cluster. A search with DALI revealed that the [4Fe-4S] cluster-binding domain is a novel structural fold. Structural analysis and comparisons with other ABC transporters revealed that this iron-sulfur cluster may act as a mediator in substrate (dipeptide or haem) binding by electron transfer and may regulate the transport process in Dpp ABC transport systems. The crystal structure provides a basis for understanding the properties of ABC transporters and will be helpful in investigating the functions of NBDs in the regulation of ABC transporter activity. << Less

  Acta Crystallogr. D 69:256-265(2013) [PubMed] [EuropePMC]

• High-throughput screening of dipeptide utilization mediated by the ABC transporter DppBCDF and its substrate-binding proteins DppA1-A5 in Pseudomonas aeruginosa.

  Pletzer D., Lafon C., Braun Y., Koehler T., Page M.G., Mourez M., Weingart H.

  In this study, we show that the dppBCDF operon of Pseudomonas aeruginosa PA14 encodes an ABC transporter responsible for the utilization of di/tripeptides. The substrate specificity of ABC transporters is determined by its associated substrate-binding proteins (SBPs). Whereas in E. coli only one p ... >> More

  In this study, we show that the dppBCDF operon of Pseudomonas aeruginosa PA14 encodes an ABC transporter responsible for the utilization of di/tripeptides. The substrate specificity of ABC transporters is determined by its associated substrate-binding proteins (SBPs). Whereas in E. coli only one protein, DppA, determines the specificity of the transporter, five orthologous SBPs, DppA1-A5 are present in P. aeruginosa. Multiple SBPs might broaden the substrate specificity by increasing the transporter capacity. We utilized the Biolog phenotype MicroArray technology to investigate utilization of di/tripeptides in mutants lacking either the transport machinery or all of the five SBPs. This high-throughput method enabled us to screen hundreds of dipeptides with various side-chains, and subsequently, to determine the substrate profile of the dipeptide permease. The substrate spectrum of the SBPs was elucidated by complementation of a penta mutant, deficient of all five SBPs, with plasmids carrying individual SBPs. It became apparent that some dipeptides were utilized with different affinity for each SBP. We found that DppA2 shows the highest flexibility on substrate recognition and that DppA2 and DppA4 have a higher tendency to utilize tripeptides. DppA5 was not able to complement the penta mutant under our screening conditions. Phaseolotoxin, a toxic tripeptide inhibiting the enzyme ornithine carbamoyltransferase, is also transported into P. aeruginosa via the DppBCDF permease. The SBP DppA1, and with much greater extend DppA3, are responsible for delivering the toxin to the permease. Our results provide a first overview of the substrate pattern of the ABC dipeptide transport machinery in P. aeruginosa. << Less

  PLoS ONE 9:e111311-e111311(2014) [PubMed] [EuropePMC]