4DXC

Crystal structure of the engineered MBP TEM-1 fusion protein RG13, C2 space group


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.30 Å
  • R-Value Free: 0.291 
  • R-Value Work: 0.233 
  • R-Value Observed: 0.236 

Starting Models: experimental
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wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

Structure of an Engineered beta-Lactamase Maltose Binding Protein Fusion Protein: Insights into Heterotropic Allosteric Regulation.

Ke, W.Laurent, A.H.Armstrong, M.D.Chen, Y.Smith, W.E.Liang, J.Wright, C.M.Ostermeier, M.van den Akker, F.

(2012) PLoS One 7: e39168-e39168

  • DOI: https://doi.org/10.1371/journal.pone.0039168
  • Primary Citation of Related Structures:  
    4DXB, 4DXC

  • PubMed Abstract: 

    Engineering novel allostery into existing proteins is a challenging endeavor to obtain novel sensors, therapeutic proteins, or modulate metabolic and cellular processes. The RG13 protein achieves such allostery by inserting a circularly permuted TEM-1 β-lactamase gene into the maltose binding protein (MBP). RG13 is positively regulated by maltose yet is, serendipitously, inhibited by Zn(2+) at low µM concentration. To probe the structure and allostery of RG13, we crystallized RG13 in the presence of mM Zn(2+) concentration and determined its structure. The structure reveals that the MBP and TEM-1 domains are in close proximity connected via two linkers and a zinc ion bridging both domains. By bridging both TEM-1 and MBP, Zn(2+) acts to "twist tie" the linkers thereby partially dislodging a linker between the two domains from its original catalytically productive position in TEM-1. This linker 1 contains residues normally part of the TEM-1 active site including the critical β3 and β4 strands important for activity. Mutagenesis of residues comprising the crystallographically observed Zn(2+) site only slightly affected Zn(2+) inhibition 2- to 4-fold. Combined with previous mutagenesis results we therefore hypothesize the presence of two or more inter-domain mutually exclusive inhibitory Zn(2+) sites. Mutagenesis and molecular modeling of an intact TEM-1 domain near MBP within the RG13 framework indicated a close surface proximity of the two domains with maltose switching being critically dependent on MBP linker anchoring residues and linker length. Structural analysis indicated that the linker attachment sites on MBP are at a site that, upon maltose binding, harbors both the largest local Cα distance changes and displays surface curvature changes, from concave to relatively flat becoming thus less sterically intrusive. Maltose activation and zinc inhibition of RG13 are hypothesized to have opposite effects on productive relaxation of the TEM-1 β3 linker region via steric and/or linker juxtapositioning mechanisms.


  • Organizational Affiliation

    Departments of Biochemistry, Case Western Reserve University, Cleveland, Ohio, United States of America.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Maltose-binding periplasmic protein, Beta-lactamase TEM chimera637Escherichia coliMutation(s): 0 
Gene Names: malEbla
EC: 3.5.2.6
UniProt
Find proteins for P0AEX9 (Escherichia coli (strain K12))
Explore P0AEX9 
Go to UniProtKB:  P0AEX9
Find proteins for P62593 (Escherichia coli)
Explore P62593 
Go to UniProtKB:  P62593
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupsP62593P0AEX9
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.30 Å
  • R-Value Free: 0.291 
  • R-Value Work: 0.233 
  • R-Value Observed: 0.236 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 124.45α = 90
b = 47.844β = 114.14
c = 108.288γ = 90
Software Package:
Software NamePurpose
HKL-2000data collection
REFMACrefinement
HKL-2000data reduction
HKL-2000data scaling
PHASERphasing

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2012-08-08
    Type: Initial release
  • Version 1.1: 2017-07-26
    Changes: Source and taxonomy
  • Version 1.2: 2023-09-13
    Changes: Data collection, Database references, Derived calculations, Refinement description