4J1U

Crystal structure of antibody 93F3 unstable variant


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.58 Å
  • R-Value Free: 0.276 
  • R-Value Work: 0.210 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Somatic hypermutation maintains antibody thermodynamic stability during affinity maturation.

Wang, F.Sen, S.Zhang, Y.Ahmad, I.Zhu, X.Wilson, I.A.Smider, V.V.Magliery, T.J.Schultz, P.G.

(2013) Proc.Natl.Acad.Sci.USA 110: 4261-4266

  • DOI: 10.1073/pnas.1301810110

  • PubMed Abstract: 
  • Somatic hypermutation and clonal selection lead to B cells expressing high-affinity antibodies. Here we show that somatic mutations not only play a critical role in antigen binding, they also affect the thermodynamic stability of the antibody molecul ...

    Somatic hypermutation and clonal selection lead to B cells expressing high-affinity antibodies. Here we show that somatic mutations not only play a critical role in antigen binding, they also affect the thermodynamic stability of the antibody molecule. Somatic mutations directly involved in antigen recognition by antibody 93F3, which binds a relatively small hapten, reduce the melting temperature compared with its germ-line precursor by up to 9 °C. The destabilizing effects of these mutations are compensated by additional somatic mutations located on surface loops distal to the antigen binding site. Similarly, somatic mutations enhance both the affinity and thermodynamic stability of antibody OKT3, which binds the large protein antigen CD3. Analysis of the crystal structures of 93F3 and OKT3 indicates that these somatic mutations modulate antibody stability primarily through the interface of the heavy and light chain variable domains. The historical view of antibody maturation has been that somatic hypermutation and subsequent clonal selection increase antigen-antibody specificity and binding energy. Our results suggest that this process also optimizes protein stability, and that many peripheral mutations that were considered to be neutral are required to offset deleterious effects of mutations that increase affinity. Thus, the immunological evolution of antibodies recapitulates on a much shorter timescale the natural evolution of enzymes in which function and thermodynamic stability are simultaneously enhanced through mutation and selection.


    Organizational Affiliation

    Department of Chemistry, The Scripps Research Institute, La Jolla, CA 92037, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
antibody 93F3 Light chain
A, C, E
219N/AMutation(s): 0 
Protein Feature View is not available: No corresponding UniProt sequence found.
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
antibody 93F3 Heavy chain
B, D, F
238N/AMutation(s): 0 
Protein Feature View is not available: No corresponding UniProt sequence found.
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.58 Å
  • R-Value Free: 0.276 
  • R-Value Work: 0.210 
  • Space Group: P 1 21 1
Unit Cell:
Length (Å)Angle (°)
a = 81.031α = 90.00
b = 112.571β = 115.28
c = 86.509γ = 90.00
Software Package:
Software NamePurpose
PHASESphasing
HKL-3000data collection
HKL-3000data reduction
HKL-3000data scaling
REFMACrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

  • Deposited Date: 2013-02-02 
  • Released Date: 2013-03-13 
  • Deposition Author(s): Wang, F.

Revision History 

  • Version 1.0: 2013-03-13
    Type: Initial release
  • Version 1.1: 2013-05-22
    Type: Database references