4IKZ

Crystal structure of peptide transporter POT (E310Q mutant) in complex with alafosfalin


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.40 Å
  • R-Value Free: 0.288 
  • R-Value Work: 0.238 
  • R-Value Observed: 0.241 

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Ligand Structure Quality Assessment 


This is version 1.2 of the entry. See complete history


Literature

Structural basis for dynamic mechanism of proton-coupled symport by the peptide transporter POT.

Doki, S.Kato, H.E.Solcan, N.Iwaki, M.Koyama, M.Hattori, M.Iwase, N.Tsukazaki, T.Sugita, Y.Kandori, H.Newstead, S.Ishitani, R.Nureki, O.

(2013) Proc Natl Acad Sci U S A 110: 11343-11348

  • DOI: https://doi.org/10.1073/pnas.1301079110
  • Primary Citation of Related Structures:  
    4IKV, 4IKW, 4IKX, 4IKY, 4IKZ

  • PubMed Abstract: 

    Proton-dependent oligopeptide transporters (POTs) are major facilitator superfamily (MFS) proteins that mediate the uptake of peptides and peptide-like molecules, using the inwardly directed H(+) gradient across the membrane. The human POT family transporter peptide transporter 1 is present in the brush border membrane of the small intestine and is involved in the uptake of nutrient peptides and drug molecules such as β-lactam antibiotics. Although previous studies have provided insight into the overall structure of the POT family transporters, the question of how transport is coupled to both peptide and H(+) binding remains unanswered. Here we report the high-resolution crystal structures of a bacterial POT family transporter, including its complex with a dipeptide analog, alafosfalin. These structures revealed the key mechanistic and functional roles for a conserved glutamate residue (Glu310) in the peptide binding site. Integrated structural, biochemical, and computational analyses suggested a mechanism for H(+)-coupled peptide symport in which protonated Glu310 first binds the carboxyl group of the peptide substrate. The deprotonation of Glu310 in the inward open state triggers the release of the bound peptide toward the intracellular space and salt bridge formation between Glu310 and Arg43 to induce the state transition to the occluded conformation.


  • Organizational Affiliation

    Department of Biophysics and Biochemistry, Graduate School of Science, The University of Tokyo, Bunkyo-ku, 113-0033 Tokyo, Japan.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Di-tripeptide ABC transporter (Permease)507Geobacillus kaustophilusMutation(s): 0 
Gene Names: GK2020
Membrane Entity: Yes 
UniProt
Find proteins for Q5KYD1 (Geobacillus kaustophilus (strain HTA426))
Explore Q5KYD1 
Go to UniProtKB:  Q5KYD1
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ5KYD1
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.40 Å
  • R-Value Free: 0.288 
  • R-Value Work: 0.238 
  • R-Value Observed: 0.241 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 53.527α = 90
b = 94.083β = 112.65
c = 57.859γ = 90
Software Package:
Software NamePurpose
SCALEPACKdata scaling
PHENIXrefinement
PDB_EXTRACTdata extraction
HKL-2000data reduction
MOLREPphasing

Structure Validation

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Ligand Structure Quality Assessment 


Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2013-07-10
    Type: Initial release
  • Version 1.1: 2022-08-24
    Changes: Database references, Derived calculations
  • Version 1.2: 2024-05-29
    Changes: Data collection