7TJC

VHH Chl-B2 in complex with Chloramphenicol


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.35 Å
  • R-Value Free: 0.235 
  • R-Value Work: 0.200 
  • R-Value Observed: 0.202 

Starting Model: experimental
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wwPDB Validation   3D Report Full Report


Ligand Structure Quality Assessment 


This is version 1.2 of the entry. See complete history


Literature

Structure and specificity of an anti-chloramphenicol single domain antibody for detection of amphenicol residues.

Swofford, C.A.Nordeen, S.A.Chen, L.Desai, M.M.Chen, J.Springs, S.L.Schwartz, T.U.Sinskey, A.J.

(2022) Protein Sci 31: e4457-e4457

  • DOI: https://doi.org/10.1002/pro.4457
  • Primary Citation of Related Structures:  
    7TJC

  • PubMed Abstract: 

    Antibiotics in aquaculture prevent bacterial infection of fish, but their misuse is a public health risk and contributes to the unintentional creation of multiresistant pathogens. Regulatory agencies cannot do the rigorous, expensive testing required to keep up with the volume of seafood shipments. Current rapid test kits for these drugs enable the increase in testing needed for adequate monitoring of food supply chains, but they lack a high degree of accuracy. To combat this, we set out to discover and engineer single-domain antibodies (VHHs) that bind to small molecule antibiotics, and that can be used in rapid test kits. The small size, solubility, and stability of VHHs are useful properties that can improve the reliability and shelf-life of test kits for these adulterants. Here, we report a novel anti-chloramphenicol VHH (Chl-VHH) with a disassociation constant of 57 nM. This was achieved by immunizing a llama against a chloramphenicol-keyhole limpet hemocyanin (KLH) conjugate and screening for high affinity binders through phage display. The crystal structure of the bound-VHH to chloramphenicol was key to identifying a mutation in the binding pocket that resulted in a 16-fold improvement in binding affinity. In addition, the structure provides new insights into VHH-hapten interactions that can guide future engineering of VHHs against additional targets.


  • Organizational Affiliation

    Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
VHH-Chl-B2
A, B
138Vicugna pacosMutation(s): 0 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.35 Å
  • R-Value Free: 0.235 
  • R-Value Work: 0.200 
  • R-Value Observed: 0.202 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 43.219α = 90
b = 66.553β = 90
c = 93.165γ = 90
Software Package:
Software NamePurpose
XDSdata reduction
XSCALEdata scaling
PHASERphasing
PHENIXrefinement
PDB_EXTRACTdata extraction

Structure Validation

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Ligand Structure Quality Assessment 


Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)United StatesR01GM77537
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)United StatesT32GM007287

Revision History  (Full details and data files)

  • Version 1.0: 2022-11-23
    Type: Initial release
  • Version 1.1: 2023-10-25
    Changes: Data collection, Refinement description
  • Version 1.2: 2024-10-23
    Changes: Structure summary