Novel Mutations in MPT64 Secretory Protein of Mycobacterium tuberculosis Complex

Area of Science:

• Genomics
• Microbiology
• Protein Science

Background:

• Tuberculosis (TB) remains a significant global health challenge caused by Mycobacterium tuberculosis complex (MTBC).
• Secreted proteins like MPT64 are crucial for MTBC pathogenesis and persistence, with MPT64 being vital for rapid TB diagnosis.
• Understanding genetic variations in key MTBC proteins is essential for improving diagnostic strategies.

Purpose of the Study:

• To investigate mutations within the highly conserved MPT64 gene in Mycobacterium tuberculosis isolates from Khyber Pakhtunkhwa Province, Pakistan.
• To analyze the impact of identified mutations on MPT64 protein structure, dynamics, and stability.
• To provide insights for enhanced TB diagnosis and management in high TB-burden countries.

Main Methods:

• Whole-genome sequencing of 470 Mycobacterium tuberculosis isolates.
• Screening for MPT64 gene mutations using TB-Profiler and BioEdit software.
• In silico analysis of mutation effects on protein stability and dynamics using the DynaMut web server.

Main Results:

• Three non-synonymous mutations (G211T, T480C, A491C) were detected in nine isolates, alongside one synonymous mutation (G208A) in four isolates.
• The G211T (F159L) mutation at the C-terminal domain was the most prevalent, found in six isolates.
• All identified non-synonymous mutations were predicted to be destabilizing to the MPT64 protein structure, with varying effects on molecular flexibility.

Conclusions:

• The MPT64 protein, despite being highly conserved, harbors specific mutations in Pakistani TB isolates.
• Identified mutations can destabilize the MPT64 protein structure, potentially affecting its diagnostic utility.
• This research offers valuable data for refining TB diagnostic approaches in regions with a high TB burden.