3E8U

Crystal structure and thermodynamic analysis of diagnostic Fab 106.3 complexed with BNP 5-13 (C10A) reveal basis of selective molecular recognition


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.10 Å
  • R-Value Free: 0.243 
  • R-Value Work: 0.185 
  • R-Value Observed: 0.188 

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Literature

Crystal structure and thermodynamic analysis of diagnostic mAb 106.3 complexed with BNP 5-13 (C10A).

Longenecker, K.L.Ruan, Q.Fry, E.H.Saldana, S.C.Brophy, S.E.Richardson, P.L.Tetin, S.Y.

(2009) Proteins 76: 536-547

  • DOI: 10.1002/prot.22366
  • Primary Citation of Related Structures:  
    3E8U

  • PubMed Abstract: 
  • B-type natriuretic peptide (BNP) is a naturally secreted regulatory hormone that influences blood pressure and vascular water retention in human physiology. The plasma BNP concentration is a clinically recognized biomarker for various cardiovascular diseases ...

    B-type natriuretic peptide (BNP) is a naturally secreted regulatory hormone that influences blood pressure and vascular water retention in human physiology. The plasma BNP concentration is a clinically recognized biomarker for various cardiovascular diseases. Quantitative detection of BNP can be achieved in immunoassays using the high-affinity monoclonal IgG1 antibody 106.3, which binds an epitope spanning residues 5-13 of the mature bioactive peptide. To understand the structural basis of this molecular recognition, we crystallized the Fab fragment complexed with the peptide epitope and determined the three-dimensional structure by X-ray diffraction to 2.1 A resolution. The structure reveals the detailed interactions that five of the complementarity-determining regions make with the partially folded peptide. Thermodynamic measurements using fluorescence spectroscopy suggest that the interaction is enthalpy driven, with an overall change in free energy of binding, DeltaG = -54 kJ/mol, at room temperature. The parameters are interpreted on the basis of the structural information. The kinetics of binding suggest a diffusion-limited mechanism, whereby the peptide easily adopts a bound conformation upon interaction with the antibody. Moreover, comparative analysis with alanine-scanning results of the epitope explains the basis of selectivity for BNP over other related natriuretic peptides.


    Organizational Affiliation

    Advanced Technology, Global Pharmaceutical Research and Development, Abbott Park, Illinois 60064, USA.



Macromolecules
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Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Fab 106.3 heavy chainA [auth H]217Mus musculusMutation(s): 0 
Protein Feature View
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  • Reference Sequence
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Entity ID: 2
MoleculeChainsSequence LengthOrganismDetailsImage
Fab 106.3 light chainB [auth L]216Mus musculusMutation(s): 0 
Protein Feature View
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  • Reference Sequence
  • Find similar proteins by:  Sequence   |   Structure
Entity ID: 3
MoleculeChainsSequence LengthOrganismDetailsImage
BNP peptide epitopeC [auth P]11N/AMutation(s): 0 
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.10 Å
  • R-Value Free: 0.243 
  • R-Value Work: 0.185 
  • R-Value Observed: 0.188 
  • Space Group: C 2 2 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 77.9α = 90
b = 88.878β = 90
c = 138.509γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
REFMACrefinement
PDB_EXTRACTdata extraction
HKL-2000data collection
HKL-2000data reduction
HKL-2000data scaling
MOLREPphasing

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2009-07-07
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2017-10-25
    Changes: Refinement description