Multi-Modal Mass Spectrometry Identifies a Conserved Protective Epitope in S. pyogenes Streptolysin O
preprint · bioRxiv · 2023
| Date | 2023-12-02 |
| Type | preprint |
| Venue | bioRxiv |
| Publisher | Cold Spring Harbor Laboratory |
| Contribution | downstream-application |
| DOI | 10.1101/2023.12.02.569700 |
| Citations (OpenAlex) | 1 |
Peer-reviewed version: Multimodal Mass Spectrometry Identifies a Conserved Protective Epitope in S. pyogenes Streptolysin O (2024-05-03, Analytical Chemistry)
Abstract
An important element of antibody-guided vaccine design is the use of neutralizing/opsonic monoclonal antibodies to define protective epitopes in their native three-dimensional conformation. Here, we demonstrate a multi-modal 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 crosslinking 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 changes 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.
Cites (5)
- De novo peptide sequencing with InstaNovo: Accurate, database-free peptide identification for large scale proteomics experiments (2023) crossref
- Multienzyme deep learning models improve peptide de novo sequencing by mass spectrometry proteomics (2023) crossref
- Comprehensive evaluation of peptide de novo sequencing tools for monoclonal antibody assembly (2023) crossref
- Sequence-to-sequence translation from mass spectra to peptides with a transformer model (2023) crossref
- Computationally instrument-resolution-independent de novo peptide sequencing for high-resolution devices (2021) crossref