6OFQ

ABC transporter-associated periplasmic binding protein DppA from Helicobacter pylori in complex with peptide STSA


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.45 Å
  • R-Value Free: 0.175 
  • R-Value Work: 0.147 
  • R-Value Observed: 0.148 

wwPDB Validation   3D Report Full Report


This is version 1.1 of the entry. See complete history


Literature

Molecular Basis of Unexpected Specificity of ABC Transporter-Associated Substrate-Binding Protein DppA from Helicobacter pylori.

Rahman, M.M.Machuca, M.A.Khan, M.F.Barlow, C.K.Schittenhelm, R.B.Roujeinikova, A.

(2019) J Bacteriol 201

  • DOI: 10.1128/JB.00400-19
  • Primary Citation of Related Structures:  
    6PU3, 6OFQ

  • PubMed Abstract: 
  • The gastric pathogen Helicobacter pylori has limited ability to use carbohydrates as a carbon source, relying instead on exogenous amino acids and peptides. Uptake of certain peptides by H. pylori requires an ATP binding cassette (A ...

    The gastric pathogen Helicobacter pylori has limited ability to use carbohydrates as a carbon source, relying instead on exogenous amino acids and peptides. Uptake of certain peptides by H. pylori requires an ATP binding cassette (ABC) transporter annotated dipeptide permease (Dpp). The transporter specificity is determined by its cognate substrate-binding protein DppA, which captures ligands in the periplasm and delivers them to the permease. Here, we show that, unlike previously characterized DppA proteins, H. pylori DppA binds, with micromolar affinity, peptides of diverse amino acid sequences ranging between two and eight residues in length. We present analysis of the 1.45-Å-resolution crystal structure of its complex with the tetrapeptide STSA, which provides a structural rationale for the observed broad specificity. Analysis of the molecular surface revealed a ligand-binding pocket that is large enough to accommodate peptides of up to nine residues in length. The structure suggests that H. pylori DppA is able to recognize a wide range of peptide sequences by forming interactions primarily with the peptide main chain atoms. The loop that terminates the peptide-binding pocket in DppAs from other bacteria is significantly shorter in the H. pylori protein, providing an explanation for its ability to bind longer peptides. The subsites accommodating the two N-terminal residues of the peptide ligand make the greatest contribution to the protein-ligand binding energy, in agreement with the observation that dipeptides bind with affinity close to that of longer peptides. IMPORTANCE The World Health Organization listed Helicobacter pylori as a high-priority pathogen for antibiotic development. The potential of using peptide transporters in drug design is well recognized. We discovered that the substrate-binding protein of the ABC transporter for peptides, termed dipeptide permease, is an unusual member of its family in that it directly binds peptides of diverse amino acid sequences, ranging between two and eight residues in length. We also provided a structural rationale for the observed broad specificity. Since the ability to import peptides as a source of carbon is critical for H. pylori , our findings will inform drug design strategies based on inhibition or fusion of membrane-impermeant antimicrobials with peptides.


    Organizational Affiliation

    Department of Microbiology, Monash University, Clayton, Victoria, Australia.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Heme-binding protein A / AI-2 binding protein AA533Helicobacter pylori SS1Mutation(s): 0 
Gene Names: hbpAHPYLSS1_00287
Find proteins for A0A1U9ISL1 (Helicobacter pylori SS1)
Explore A0A1U9ISL1 
Go to UniProtKB:  A0A1U9ISL1
Protein Feature View
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  • Reference Sequence
  • Find similar proteins by:  Sequence   |   Structure
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetailsImage
SER-THR-SER-ALAB4Escherichia coliMutation(s): 0 
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.45 Å
  • R-Value Free: 0.175 
  • R-Value Work: 0.147 
  • R-Value Observed: 0.148 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 64.12α = 90
b = 75.77β = 90
c = 128.37γ = 90
Software Package:
Software NamePurpose
REFMACrefinement
XDSdata reduction
Aimlessdata scaling
MOLREPphasing

Structure Validation

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Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2019-08-21
    Type: Initial release
  • Version 1.1: 2019-10-02
    Changes: Data collection, Database references