High-resolution structure of the periplasmic ectoine-binding protein from TeaABC TRAP-transporter of Halomonas elongata

Experimental Data Snapshot

  • Resolution: 1.55 Å
  • R-Value Free: 0.204 
  • R-Value Work: 0.158 
  • R-Value Observed: 0.159 

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1.55 A Structure of the Ectoine Binding Protein Teaa of the Osmoregulated Trap-Transporter Teaabc from Halomonas Elongata.

Kuhlmann, S.I.Terwisscha Van Scheltinga, A.C.Bienert, R.Kunte, H.J.Ziegler, C.

(2008) Biochemistry 47: 9475

  • DOI: https://doi.org/10.1021/bi8006719
  • Primary Citation of Related Structures:  
    2VPN, 2VPO

  • PubMed Abstract: 

    TeaABC from the moderate halophilic bacterium Halomonas elongata belongs to the tripartite ATP-independent periplasmic transporters (TRAP-T), a family of secondary transporters functioning in conjunction with periplasmic substrate binding proteins. TeaABC facilitates the uptake of the compatible solutes ectoine and hydroxyectoine that are accumulated in the cytoplasm under hyperosmotic stress to protect the cell from dehydration. TeaABC is the only known TRAP-T activated by osmotic stress. Currently, our knowledge on the osmoregulated compatible solute transporter is limited to ABC transporters or conventional secondary transporters. Therefore, this study presents the first detailed analysis of the molecular mechanisms underlying substrate recognition of the substrate binding protein of an osmoregulated TRAP-T. In the present study we were able to demonstrate by isothermal titration calorimetry measurements that TeaA is a high-affinity ectoine binding protein ( K d = 0.19 microM) that also has a significant but somewhat lower affinity to hydroxyectoine ( K d = 3.8 microM). Furthermore, we present the structure of TeaA in complex with ectoine at a resolution of 1.55 A and hydroxyectoine at a resolution of 1.80 A. Analysis of the TeaA binding pocket and comparison of its structure to other compatible solute binding proteins from ABC transporters reveal common principles in compatible solute binding but also significant differences like the solvent-mediated specific binding of ectoine to TeaA.

  • Organizational Affiliation

    Department of Structural Biology, Max-Planck-Institute of Biophysics, Max-von-Laue-Strasse 3, 60438 Frankfurt am Main, Germany.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B
316Halomonas elongataMutation(s): 0 
Find proteins for E1VBK1 (Halomonas elongata (strain ATCC 33173 / DSM 2581 / NBRC 15536 / NCIMB 2198 / 1H9))
Explore E1VBK1 
Go to UniProtKB:  E1VBK1
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupE1VBK1
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on 4CS

Download Ideal Coordinates CCD File 
C [auth A],
H [auth B]
C6 H10 N2 O2
Query on MG

Download Ideal Coordinates CCD File 
D [auth A]
E [auth A]
F [auth A]
G [auth A]
I [auth B]
D [auth A],
E [auth A],
F [auth A],
G [auth A],
I [auth B],
J [auth B],
K [auth B],
L [auth B]
Binding Affinity Annotations 
IDSourceBinding Affinity
4CS PDBBind:  2VPN Kd: 190 (nM) from 1 assay(s)
Binding MOAD:  2VPN Kd: 190 (nM) from 1 assay(s)
Experimental Data & Validation

Experimental Data

  • Resolution: 1.55 Å
  • R-Value Free: 0.204 
  • R-Value Work: 0.158 
  • R-Value Observed: 0.159 
  • Space Group: P 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 48.3α = 80.8
b = 52.2β = 85.8
c = 63.5γ = 77.9
Software Package:
Software NamePurpose
XDSdata reduction
XSCALEdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2008-08-26
    Type: Initial release
  • Version 1.1: 2011-05-08
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2024-05-08
    Changes: Data collection, Database references, Derived calculations