2XZC

Crystal Structure of phosphonate-modified recombinant A.17 antibody FAB fragment


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.36 Å
  • R-Value Free: 0.191 
  • R-Value Work: 0.162 
  • R-Value Observed: 0.163 

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Ligand Structure Quality Assessment 


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Literature

Reactibodies Generated by Kinetic Selection Couple Chemical Reactivity with Favorable Protein Dynamics.

Smirnov, I.Carletti, E.Kurkova, I.Nachon, F.Nicolet, Y.Mitkevich, V.A.Debat, H.Avalle, B.Belogurov, A.A.Kuznetsov, N.Reshetnyak, A.Masson, P.Tonevitsky, A.G.Ponomarenko, N.Makarov, A.A.Friboulet, A.Tramontano, A.Gabibov, A.

(2011) Proc Natl Acad Sci U S A 108: 15954

  • DOI: https://doi.org/10.1073/pnas.1108460108
  • Primary Citation of Related Structures:  
    2XZA, 2XZC

  • PubMed Abstract: 

    Igs offer a versatile template for combinatorial and rational design approaches to the de novo creation of catalytically active proteins. We have used a covalent capture selection strategy to identify biocatalysts from within a human semisynthetic antibody variable fragment library that uses a nucleophilic mechanism. Specific phosphonylation at a single tyrosine within the variable light-chain framework was confirmed in a recombinant IgG construct. High-resolution crystallographic structures of unmodified and phosphonylated Fabs display a 15-Å-deep two-chamber cavity at the interface of variable light (V(L)) and variable heavy (V(H)) fragments having a nucleophilic tyrosine at the base of the site. The depth and structure of the pocket are atypical of antibodies in general but can be compared qualitatively with the catalytic site of cholinesterases. A structurally disordered heavy chain complementary determining region 3 loop, constituting a wall of the cleft, is stabilized after covalent modification by hydrogen bonding to the phosphonate tropinol moiety. These features and presteady state kinetics analysis indicate that an induced fit mechanism operates in this reaction. Mutations of residues located in this stabilized loop do not interfere with direct contacts to the organophosphate ligand but can interrogate second shell interactions, because the H3 loop has a conformation adjusted for binding. Kinetic and thermodynamic parameters along with computational docking support the active site model, including plasticity and simple catalytic components. Although relatively uncomplicated, this catalytic machinery displays both stereo- and chemical selectivity. The organophosphate pesticide paraoxon is hydrolyzed by covalent catalysis with rate-limiting dephosphorylation. This reactibody is, therefore, a kinetically selected protein template that has enzyme-like catalytic attributes.


  • Organizational Affiliation

    Institute of Bioorganic Chemistry Russian Academy of Sciences, Moscow 117997, Russia.


Macromolecules
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Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
FAB A.17 HEAVY CHAINA [auth H]222Homo sapiensMutation(s): 0 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
Sequence Annotations
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  • Reference Sequence
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Entity ID: 2
MoleculeChains Sequence LengthOrganismDetailsImage
FAB A.17 LIGHT CHAINB [auth L]216Homo sapiensMutation(s): 0 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
Sequence Annotations
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  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
XOP
Query on XOP

Download Ideal Coordinates CCD File 
D [auth L]8-METHYL-8-AZABICYCLO[3.2.1]OCTAN-3-YL PHENYLPHOSPHONATE
C14 H20 N O3 P
DUXLOXDDMDLSLH-ITGUQSILSA-N
CL
Query on CL

Download Ideal Coordinates CCD File 
C [auth H]CHLORIDE ION
Cl
VEXZGXHMUGYJMC-UHFFFAOYSA-M
Modified Residues  1 Unique
IDChains TypeFormula2D DiagramParent
PCA
Query on PCA
A [auth H]L-PEPTIDE LINKINGC5 H7 N O3GLN
Binding Affinity Annotations 
IDSourceBinding Affinity
XOP PDBBind:  2XZC Kd: 2300 (nM) from 1 assay(s)
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.36 Å
  • R-Value Free: 0.191 
  • R-Value Work: 0.162 
  • R-Value Observed: 0.163 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 52.56α = 90
b = 66.95β = 107.65
c = 66.21γ = 90
Software Package:
Software NamePurpose
REFMACrefinement
XDSdata reduction
XSCALEdata scaling

Structure Validation

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Ligand Structure Quality Assessment 


Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2011-09-21
    Type: Initial release
  • Version 1.1: 2011-10-05
    Changes: Database references
  • Version 2.0: 2020-03-11
    Changes: Derived calculations, Other, Polymer sequence