Title:Characterization of Pili Protein 67 kDa Streptococcus pneumoniae: New
Candidate for Virulence Factor-Based Pneumococcal Antigen Vaccine
Volume: 29
Issue: 8
Author(s): Diana C. Mufida*, Rahma Perwitasari, Dini Agustina, Muhammad A. Shodikin and Enny Suswati
Affiliation:
- Laboratory of Microbiology, Faculty of Medicine, University of Jember, Jember 68121, Indonesia
Keywords:
Pilus 67 kDa, S. pneumoniae, vaccine, virulence factors, gram-positive, antigen.
Abstract:
Introduction: Streptococcus pneumoniae is a Gram-positive diplococci bacteria that
causes infectious diseases such as otitis, meningitis, and pneumonia. Streptococcus pneumoniae has
various virulence factors, one of which is pilus. In addition to being immunogenic, pilus S.
pneumoniae also plays a role in bacterial adhesion to host cells and biofilm formation. The S.
pneumoniae pilus found in this study consisted of several proteins with various molecular weights,
one of which was a 67 kDa protein.
Objective: This study aimed to determine the characteristics of the 67 kDa pilus protein, including
its capacity as hemagglutinin and adhesin and its amino acid sequence (AA).
Methods: The LCMS/MS method is used to determine the AA sequence of the 67 kDa pilus
protein. The AA structure was analyzed through BLASTP by matching it with the sequence of the
protein data bank of S. pneumoniae (taxid: 1313). The ProtParam tool from ExPASY was used to
calculate various physical and chemical parameters of the protein, while for evaluating its
immunogenicity, the VaxiJen V2.0 online server was used.
Results: The results of this study indicate that the 67 kD a pilus protein, is an anti-hemagglutinin
protein and has a role as an adhesin protein. Adhesion tests show the action between protein
concentration and the number of bacteria attached to enterocyte cells. LCMS/MS test results
obtained by BLASTP showed that the 67 kDa pilus protein had three AA sequences
(ITYMSPDFAAPTLAGLDDATK, AEFVEVTK, and LVVSTQTALA), which had similarities with
the A backbone chain of S. pneumoniae pilus. The physicochemical test showed that the protein is
hydrophilic and nonpolar, while the antigenicity test showed that the protein is antigenic.
Conclusion: Based on these characteristics, it can be concluded that the 67 kDa S. pneumoniae
pilus protein can be used as a vaccine candidate for pneumococcus.