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The presence of excessive hydrogen sulfide (H 2 S)-producing bacteria, particularly Bilophila wadsworthia in appendices, is linked to a weaker colonic mucus barrier, inflammatory bowel disease, and colorectal cancer. Thus, targeting this bacterium could reduce sulfide levels and address associated health concerns. Here, we utilized reverse vaccinology and immunoinformatics to design a chimeric vaccine against B. wadsworthia , focusing on membrane-bound and extracellular proteins. Subtractive proteome analysis identified 18 potential vaccine candidates (PVCs), from which six B-cell, eight CD8+ T cell, and six CD4+ T cell epitopes were predicted. Chosen epitopes were assessed for immunological properties and cross-reactivity with human and mouse proteomes. Subsequently, these epitopes were fused with appropriate linkers, PADRE epitope, TAT peptide, and Cholera Toxin B subunit adjuvant to form a robust multi-epitope vaccine (MEV). The MEV's tertiary structure was modelled and validated for reliable analysis. Molecular docking and dynamics simulations demonstrated stable binding of MEV with Toll-like receptor 4. The MEV showed favorable physicochemical characteristics, high expression potential in Escherichia coli , broad population coverage (∼98 %), and cross-protection against different B. wadsworthia strains. Immune simulation suggested induction of strong B and T cell responses, including primary, secondary, and tertiary immune responses. Further experimental studies are necessary to validate these findings. [ABSTRACT FROM AUTHOR]

Bilophila wadsworthia is one of the prominent sources of hydrogen sulfide (H 2 S) production in appendices, excessive levels of which can result in a weaker colonic mucus barrier, inflammatory bowel disease, and colorectal cancer. Isethionate sulfite-lyase (IslA) enzyme catalyzes H 2 S production by cleaving C S bond in isethionate, producing acetaldehyde and sulfite. In this study, we aimed to identify potential substrate antagonists for IsIA using a structure-based drug design. Initially, pharmacophore-based computational screening of the ZINC20 database yielded 66 hits that were subjected to molecular docking targeting the isethionate binding site of IsIA. Based on striking docking scores, nine compounds showed strong interaction with critical IsIA residues (Arg189, Gln193, Glu470, Cys468, and Arg678), drug-like features, appropriate adsorption, metabolism, excretion, and excretion profile with non-toxicity. Molecular dynamics simulations uncovered the significant impact of binding the compounds on protein conformational dynamics. Finally, binding free energies revealed substantial binding affinity (ranging from −35.23 to −53.88 kcal/mol) of compounds (ZINC913876497, ZINC913856647, ZINC914263733, ZINC914137795, ZINC915757996, ZINC914357083, ZINC913934833, ZINC9143362047, and ZINC913854740) for IsIA. The compounds proposed herein through a multi-faceted computational strategy can be experimentally validated as potential substrate antagonists of B. wadsworthia 's IsIA for developing new medications to curb gut-associated illness in the future. [ABSTRACT FROM AUTHOR]