Multimodal Mass Spectrometry Identifies a Conserved Protective Epitope in S. pyogenes Streptolysin O
peer-reviewed · Analytical Chemistry · 2024
| Date | 2024-05-03 |
| Type | peer-reviewed |
| Venue | Analytical Chemistry |
| Publisher | American Chemical Society |
| Contribution | downstream-application |
| DOI | 10.1021/acs.analchem.4c00596 |
| Citations (OpenAlex) | 11 |
| Venue 2-year citedness | 6.29 |
Preprint version: Multi-Modal Mass Spectrometry Identifies a Conserved Protective Epitope in S. pyogenes Streptolysin O (2023-12-02, bioRxiv)
Abstract
High Resolution Image Download MS PowerPoint Slide An important element of antibody-guided vaccine design is the use of neutralizing or opsonic monoclonal antibodies to define protective epitopes in their native three-dimensional conformation. Here, we demonstrate a multimodal mass spectrometry-based strategy for in-depth characterization of antigen–antibody complexes to enable the identification of protective epitopes using the cytolytic exotoxin Streptolysin O (SLO) from Streptococcus pyogenes as a showcase. We first discovered a monoclonal antibody with an undisclosed sequence capable of neutralizing SLO-mediated cytolysis. The amino acid sequence of both the antibody light and the heavy chain was determined using mass-spectrometry-based de novo sequencing, followed by chemical cross-linking mass spectrometry to generate distance constraints between the antibody fragment antigen-binding region and SLO. Subsequent integrative computational modeling revealed a discontinuous epitope located in domain 3 of SLO that was experimentally validated by hydrogen–deuterium exchange mass spectrometry and reverse engineering of the targeted epitope. The results show that the antibody inhibits SLO-mediated cytolysis by binding to a discontinuous epitope in domain 3, likely preventing oligomerization and subsequent secondary structure transitions critical for pore-formation. The epitope is highly conserved across >98% of the characterized S. pyogenes isolates, making it an attractive target for antibody-based therapy and vaccine design against severe streptococcal infections.
Methods and tools
- Streptolysin O epitope de novo workflow: Multi-modal MS workflow combining three deep-learning de novo sequencers (PointNovo, Casanovo, InstaNovo) with antibody profiling to identify a conserved protective epitope in Streptococcus pyogenes Streptolysin O.
Cited by (1)
- Deep Learning Methods for De Novo Peptide Sequencing (2024) crossref