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Characterization of Pili Protein 67 kDa Streptococcus pneumoniae: New Candidate for Virulence Factor-Based
Diana C Mufida1, Rahma Perwitasari2, Dini Agustina1
1Laboratory of Microbiology, Faculty of Medicine, University of Jember, Jember 68121, Indonesia.
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.
Insights
The 67 kDa pilus protein from Streptococcus pneumoniae acts as an adhesin and is antigenic. This protein shows potential as a vaccine candidate against pneumococcal infections.
Area of Science:
- Microbiology
- Immunology
- Biochemistry
Background:
- Streptococcus pneumoniae causes various infections like meningitis and pneumonia.
- Pilus proteins are key virulence factors, aiding in bacterial adhesion and biofilm formation.
- A 67 kDa pilus protein was identified in S. pneumoniae.
Purpose of the Study:
- To characterize the 67 kDa pilus protein of S. pneumoniae.
- To determine its hemagglutinin and adhesin properties.
- To elucidate its amino acid sequence and physicochemical properties.
Main Methods:
- Liquid chromatography-tandem mass spectrometry (LC-MS/MS) for amino acid sequencing.
- BLASTP analysis against the S. pneumoniae protein database.
- ProtParam tool for physicochemical analysis and VaxiJen V2.0 for immunogenicity assessment.
Main Results:
- The 67 kDa protein functions as an anti-hemagglutinin and adhesin.
- Adhesion assays demonstrated a correlation between protein concentration and bacterial attachment.
- LC-MS/MS identified three amino acid sequences with similarity to the S. pneumoniae pilus A backbone.
- Physicochemical analysis revealed the protein to be hydrophilic, nonpolar, and antigenic.
Conclusions:
- The 67 kDa S. pneumoniae pilus protein exhibits characteristics suitable for vaccine development.
- Its adhesin role and antigenicity support its potential as a pneumococcal vaccine candidate.
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