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Analyzing Protein Architectures and Protein-Ligand Complexes by Integrative Structural Mass Spectrometry
Published on: October 15, 2018
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Novel Structural Parameters of Ig-Ag Complexes Yield a Quantitative Description of Interaction Specificity and
Simon Marillet1, Marie-Paule Lefranc2, Pierre Boudinot3
1VIM, INRA and Université Paris-Saclay, Jouy-en-josas, France; Université Côte d'Azur and Inria, Sophia Antipolis, France.
Frontiers in Immunology
|February 25, 2017
Summary
We developed a novel method to predict antibody-antigen binding affinity by analyzing interface structures. This approach accurately classifies ligand types and identifies key antibody complementarity-determining regions (CDRs) driving binding specificity.
Area of Science:
- Immunology and Structural Biology
- Computational Biology and Bioinformatics
Background:
- Antibody-antigen interactions are crucial in immunology but their binding affinity and specificity determinants remain incompletely understood.
- Existing analyses have not fully elucidated the key factors governing the strength and specificity of these molecular interactions.
Purpose of the Study:
- To develop a quantitative analysis for predicting antibody-antigen binding affinity.
- To classify ligand types involved in antibody binding.
- To identify the contributions of antibody complementarity-determining regions (CDRs) to binding affinity.
Main Methods:
- Utilized two standardized databases: IMGT/3Dstructure-DB and a structure-affinity benchmark.
- Performed statistical analysis of antibody-antigen interfaces.
- Quantified the positional and atomic packing contributions of CDRs to binding affinity.
Main Results:
- Achieved accurate classification of ligand types (protein, peptide, chemical) with a 9.6% cross-validated error.
- Obtained highly accurate binding affinity predictions with a median absolute error of 0.878 kcal/mol.
- Demonstrated that VH CDR3 and VL CDR3 generally make dominant contributions to binding affinity, consistent with enthalpy-entropy compensation.
Conclusions:
- Antibody-antigen binding affinity prediction can be significantly advanced using quantitative analysis of high-resolution crystal structures.
- The study highlights the critical role of specific CDRs, particularly CDR3, in determining binding strength.
- This work provides a foundation for improved computational tools in antibody engineering and drug discovery.
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