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Structure-based Epitope Mapping of Mycobacterium tuberculosis Secretary Antigen MTC28
Prasun Kundu1, Rupam Biswas1, Somnath Mukherjee1
1Department of Biotechnology, Indian Institute of Technology Kharagpur, West Bengal 721302, India.
The Journal of Biological Chemistry
|May 19, 2016
Summary
Researchers identified key immunogenic epitopes on MTC28, a Mycobacterium tuberculosis antigen crucial for infection. These findings advance structure-based epitope design for developing diagnostics and therapeutics against pulmonary tuberculosis (PTB).
Area of Science:
- Structural Biology
- Immunology
- Microbiology
Background:
- Secretary proteins of Mycobacterium tuberculosis are vital in mycobacterial infection.
- MTC28 is a 28-kDa proline-rich antigen conserved in pathogenic mycobacteria.
Purpose of the Study:
- To determine the crystal structure of MTC28 for structure-based epitope design.
- To identify immunogenic epitopes on MTC28 for potential diagnostic and therapeutic applications.
Main Methods:
- Crystal structure determination of MTC28 at 2.8- and 2.15-Å resolutions.
- Computational epitope prediction using the MTC28 structure.
- Trypsin digestion of MTC28, purification of peptide fragments by HPLC, and screening against sera from pulmonary tuberculosis patients.
- Mutagenesis and antibody inhibition studies.
Main Results:
- The crystal structure revealed MTC28 adopts a "mog1p"-fold.
- Five probable epitopes were computationally predicted on a flexible region.
- Two peptide fragments, (127)ALDITLPMPPR(137) and (138)WTQVPDPNVPDAFVVIADR(156), were identified as major immunogenic epitopes.
- These epitopes are surface-localized and form a single continuous epitope.
Conclusions:
- The study successfully mapped major immunogenic epitopes on MTC28.
- These identified epitopes are suitable for structure-based epitope design in tuberculosis research.
- Findings support the development of novel diagnostics and therapeutics targeting MTC28 in pulmonary tuberculosis.
