1ZKB

Zinc-free Engineered maltose binding protein


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.20 Å
  • R-Value Free: 0.285 
  • R-Value Work: 0.244 
  • R-Value Observed: 0.264 

wwPDB Validation   3D Report Full Report


This is version 1.5 of the entry. See complete history


Literature

Structural studies of an engineered zinc biosensor reveal an unanticipated mode of zinc binding.

Telmer, P.G.Shilton, B.H.

(2005) J Mol Biol 354: 829-840

  • DOI: https://doi.org/10.1016/j.jmb.2005.10.016
  • Primary Citation of Related Structures:  
    1ZIU, 1ZJL, 1ZKB, 1ZMG

  • PubMed Abstract: 

    Protein engineering was used previously to convert maltose-binding protein (MBP) into a zinc biosensor. Zn(2+) binding by the engineered MBP was thought to require a large conformational change from "open" to "closed", similar to that observed when maltose is bound by the wild-type protein. We show that although this re-designed MBP molecule binds Zn(2+) with high affinity as previously reported, it does not adopt a closed conformation in solution as assessed by small-angle X-ray scattering. High-resolution crystallographic studies of the engineered Zn(2+)-binding MBP molecule demonstrate that Zn(2+) is coordinated by residues on the N-terminal lobe only, and therefore Zn(2+) binding does not require the protein to adopt a fully closed conformation. Additional crystallographic studies indicate that this unexpected Zn(2+) binding site can also coordinate Cu(2+) and Ni(2+) with only subtle changes in the overall conformation of the protein. This work illustrates that the energetic barrier to domain closure, which normally functions to maintain MBP in an open concentration in the absence of ligand, is not easily overcome by protein design. A comparison to the mechanism of maltose-induced domain rearrangement is discussed.


  • Organizational Affiliation

    Department of Biochemistry, University of Western Ontario, London, Ontari, Canada N6A 5C1.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Maltose-binding periplasmic protein370Escherichia coliMutation(s): 5 
Gene Names: malE
UniProt
Find proteins for P0AEX9 (Escherichia coli (strain K12))
Explore P0AEX9 
Go to UniProtKB:  P0AEX9
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP0AEX9
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.20 Å
  • R-Value Free: 0.285 
  • R-Value Work: 0.244 
  • R-Value Observed: 0.264 
  • Space Group: P 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 37.58α = 100.25
b = 44.01β = 101.74
c = 57.35γ = 102.16
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
AMoREphasing
CNSrefinement

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2005-12-20
    Type: Initial release
  • Version 1.1: 2008-04-30
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2017-10-11
    Changes: Refinement description
  • Version 1.4: 2021-10-20
    Changes: Database references
  • Version 1.5: 2023-08-23
    Changes: Data collection, Refinement description