Understanding Rifampicin Resistance in Tuberculosis through a Computational Approach

Area of Science:

• Molecular Biology
• Drug Discovery
• Computational Biology

Background:

• Tuberculosis (TB), caused by Mycobacterium tuberculosis (MTB), is a significant global health issue, particularly in developing nations.
• The rise of drug-resistant TB, especially resistance to frontline drugs like rifampicin (RIF), is a critical threat.
• Mutations in the rpoB gene, encoding the beta subunit of RNA polymerase, are a primary cause of RIF resistance in MTB.

Purpose of the Study:

• To investigate the molecular mechanism of RIF resistance in MTB by modeling and analyzing mutations in the rpoB gene.
• To compare the binding affinity of RIF with wild-type and mutant rpoB using computational methods.

Main Methods:

• In silico modeling of two key rpoB mutants (S450L and H445Y) associated with RIF resistance using Modeller9v10.
• Molecular docking analysis of RIF with wild-type and mutant rpoB using AutoDock4.2.
• Validation of docking results through molecular dynamics simulations.

Main Results:

• Docking analysis revealed that RIF binds more effectively to wild-type rpoB, exhibiting lower binding energy.
• RIF interacted with the rpoB mutants with positive binding energy, indicating an inability of RIF to inhibit the enzyme.
• Molecular dynamics simulations confirmed these findings, supporting the in silico evidence for RIF resistance.

Conclusions:

• The study provides in silico evidence that specific mutations in the rpoB gene (S450L and H445Y) reduce the binding affinity of RIF, leading to drug resistance in Mycobacterium tuberculosis.
• These findings enhance the understanding of the molecular basis of RIF resistance and may inform future drug development strategies against resistant TB strains.