Prediction of Burkholderia pseudomallei DsbA substrates identifies potential virulence factors and vaccine targets

• Published in: PloS one 2020-11, Vol.15 (11), p.e0241306-e0241306
• Main Authors: Vezina, Ben, Petit, Guillaume A, Martin, Jennifer L, Halili, Maria A
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Antibiotic resistance; Antibiotics; Bacteria; Bacterial proteins; Bacterial Proteins - metabolism; Bacterial vaccines; Bacterial Vaccines - immunology; Biology and Life Sciences; Burkholderia; Burkholderia pseudomallei; Burkholderia pseudomallei - genetics; Burkholderia pseudomallei - immunology; Burkholderia pseudomallei - pathogenicity; Chemical bonds; Cysteine - metabolism; Disulfide bonds; Drug discovery; Epitopes; Epitopes, B-Lymphocyte - chemistry; Epitopes, B-Lymphocyte - immunology; Gene Ontology; Genetic aspects; Genome, Bacterial; Genomes; Genomic analysis; Health aspects; Homology; Identification and classification; Immunization; Infections; Lymphocytes B; Medicine and Health Sciences; Melioidosis; Metadata; Methods; Models, Molecular; Molecular targeted therapy; Pathogenesis; Pathogens; Pharmacological research; Physical Sciences; Protein A; Proteins; Sequence Homology, Amino Acid; Substrate Specificity; Substrates; Target recognition; Testing; Vaccine development; Vaccines; Virulence; Virulence (Microbiology); Virulence factors; Virulence Factors - metabolism; β Lactamase
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0241306

Identification of bacterial virulence factors is critical for understanding disease pathogenesis, drug discovery and vaccine development. In this study we used two approaches to predict virulence factors of Burkholderia pseudomallei, the Gram-negative bacterium that causes melioidosis. B. pseudomallei is naturally antibiotic resistant and there are no clinically available melioidosis vaccines. To identify B. pseudomallei protein targets for drug discovery and vaccine development, we chose to search for substrates of the B. pseudomallei periplasmic disulfide bond forming protein A (DsbA). DsbA introduces disulfide bonds into extra-cytoplasmic proteins and is essential for virulence in many Gram-negative organism, including B. pseudomallei. The first approach to identify B. pseudomallei DsbA virulence factor substrates was a large-scale genomic analysis of 511 unique B. pseudomallei disease-associated strains. This yielded 4,496 core gene products, of which we hypothesise 263 are DsbA substrates. Manual curation and database screening of the 263 mature proteins yielded 81 associated with disease pathogenesis or virulence. These were screened for structural homologues to predict potential B-cell epitopes. In the second approach, we searched the B. pseudomallei genome for homologues of the more than 90 known DsbA substrates in other bacteria. Using this approach, we identified 15 putative B. pseudomallei DsbA virulence factor substrates, with two of these previously identified in the genomic approach, bringing the total number of putative DsbA virulence factor substrates to 94. The two putative B. pseudomallei virulence factors identified by both methods are homologues of PenI family β-lactamase and a molecular chaperone. These two proteins could serve as high priority targets for future B. pseudomallei virulence factor characterization.