2B3F

Thermus thermophilus Glucose/Galactose Binding Protein Bound With Galactose


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.56 Å
  • R-Value Free: 0.205 
  • R-Value Work: 0.174 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

The crystal structure of a thermophilic glucose binding protein reveals adaptations that interconvert mono and di-saccharide binding sites.

Cuneo, M.J.Changela, A.Warren, J.J.Beese, L.S.Hellinga, H.W.

(2006) J.Mol.Biol. 362: 259-270

  • DOI: 10.1016/j.jmb.2006.06.084
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Periplasmic binding proteins (PBPs) comprise a protein superfamily that is involved in prokaryotic solute transport and chemotaxis. These proteins have been used to engineer reagentless biosensors to detect natural or non-natural ligands. There is co ...

    Periplasmic binding proteins (PBPs) comprise a protein superfamily that is involved in prokaryotic solute transport and chemotaxis. These proteins have been used to engineer reagentless biosensors to detect natural or non-natural ligands. There is considerable interest in obtaining very stable members of this superfamily from thermophilic bacteria to use as robust engineerable parts in biosensor development. Analysis of the recently determined genome sequence of Thermus thermophilus revealed the presence of more than 30 putative PBPs in this thermophile. One of these is annotated as a glucose binding protein (GBP) based on its genetic linkage to genes that are homologous to an ATP-binding cassette glucose transport system, although the PBP sequence is homologous to periplasmic maltose binding proteins (MBPs). Here we present the cloning, over-expression, characterization of cognate ligands, and determination of the X-ray crystal structure of this gene product. We find that it is a very stable (apo-protein Tm value is 100(+/- 2) degrees C; complexes 106(+/- 3) degrees C and 111(+/- 1) degrees C for glucose and galactose, respectively) glucose (Kd value is 0.08(+/- 0.03) microM) and galactose (Kd value is 0.94(+/- 0.04) microM) binding protein. Determination of the X-ray crystal structure revealed that this T. thermophilus glucose binding protein (ttGBP) is structurally homologous to MBPs rather than other GBPs. The di or tri-saccharide ligands in MBPs are accommodated in long relatively shallow grooves. In the ttGBP binding site, this groove is partially filled by two loops and an alpha-helix, which create a buried binding site that allows binding of only monosaccharides. Comparison of ttGBP and MBP provides a clear example of structural adaptations by which the size of ligand binding sites can be controlled in the PBP super family.


    Organizational Affiliation

    The Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
glucose-binding protein
A, B, C, D, E, F
400Thermus thermophilus (strain HB27 / ATCC BAA-163 / DSM 7039)Mutation(s): 0 
Find proteins for Q72KX2 (Thermus thermophilus (strain HB27 / ATCC BAA-163 / DSM 7039))
Go to UniProtKB:  Q72KX2
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
GAL
Query on GAL

Download SDF File 
Download CCD File 
A, B, C, D, E, F
BETA-D-GALACTOSE
C6 H12 O6
WQZGKKKJIJFFOK-FPRJBGLDSA-N
 Ligand Interaction
External Ligand Annotations 
IDBinding Affinity (Sequence Identity %)
GALKd: 940 nM BINDINGMOAD
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.56 Å
  • R-Value Free: 0.205 
  • R-Value Work: 0.174 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 121.376α = 90.00
b = 134.958β = 90.00
c = 159.719γ = 90.00
Software Package:
Software NamePurpose
REFMACrefinement
HKL-2000data reduction
CCP4data scaling
DENZOdata reduction
SCALEPACKdata scaling
PDB_EXTRACTdata extraction
SHELXL-97phasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2006-07-18
    Type: Initial release
  • Version 1.1: 2008-05-01
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance
  • Version 1.3: 2017-10-11
    Type: Refinement description