Characterization of the Staphylococcus aureus bone sialoprotein-binding protein SdrE and the serine protease EpiP

Prachi, Prachi (2013) Characterization of the Staphylococcus aureus bone sialoprotein-binding protein SdrE and the serine protease EpiP, [Dissertation thesis], Alma Mater Studiorum Università di Bologna. Dottorato di ricerca in Biologia cellulare, molecolare e industriale/cellular, molecular and industrial biology: progetto n. 2 Biologia funzionale dei sistemi cellulari e molecolari, 25 Ciclo. DOI 10.6092/unibo/amsdottorato/5816.
Documenti full-text disponibili:
[img]
Anteprima
Documento PDF (English) - Richiede un lettore di PDF come Xpdf o Adobe Acrobat Reader
Download (2MB) | Anteprima

Abstract

In an attempt to develop a Staphylococcus aureus vaccine, we have applied reverse vaccinology approach, mainly based on in silico screening and proteomics. By using this approach SdrE, a protein belonging to serine-aspartate repeat protein family was identified as potential vaccine antigen against S. aureus. We have investigated the biochemical properties as well as the vaccine potential of SdrE and its highly conserved CnaBE3 domain. We found the protein SdrE to be resistant to trypsin. Further analysis of the resistant fragment revealed that it comprises a CnaBE3 domain, which also showed partial trypsin resistant behavior. Furthermore, intact mass spectrometry of rCnaBE3 suggested the possible presence of isopeptide bond or some other post-translational modification in the protein.However, this observation needs further investigation. Differential Scanning Fluorimetry study reveals that calcium play role in protein folding and provides stability to SdrE. At the end we have demonstrated that SdrE is immunogenic against clinical strain of S. aureus in murine abscess model. In the second part, I characterized a protein, annotated as epidermin leader peptide processing serine protease (EpiP), as a novel S. aureus vaccine candidate. The crystal structure of the rEpiP was solved at 2.05 Å resolution by x-ray crystallography . The structure showed that rEpiP was cleaved somewhere between residues 95 and 100 and cleavage occurs through an autocatalytic intra-molecular mechanism. In addition, the protein expressed by S. aureus cells also appeared to undergo a similar processing event. To determine if the protein acts as a serine protease, we mutated the catalytic serine 393 residue to alanine, generating rEpiP-S393A and solved its crystal structure at a resolution of 1.95 Å. rEpiP-S393A was impaired in its protease activity, as expected. Protective efficacy of rEpiP and the non-cleaving mutant protein was comparable, implying that the two forms are interchangeable for vaccination purposes.

Abstract
Tipologia del documento
Tesi di dottorato
Autore
Prachi, Prachi
Supervisore
Co-supervisore
Dottorato di ricerca
Scuola di dottorato
Scienze biologiche, biomediche e biotecnologiche
Ciclo
25
Coordinatore
Settore disciplinare
Settore concorsuale
Parole chiave
Staphylococcus aureus, reverse vaccinology, proteomics, serine-aspartate repeat protein, Differential Scanning Fluorimetry , EpiP.
URN:NBN
DOI
10.6092/unibo/amsdottorato/5816
Data di discussione
22 Aprile 2013
URI

Altri metadati

Statistica sui download

Gestione del documento: Visualizza la tesi

^