Targeting PilA in Acinetobacter baumannii: A Computational Approach for Anti-Virulent Compound Discovery.

Area of Science:

• Microbiology and Infectious Diseases
• Computational Chemistry and Drug Discovery
• Molecular Biology

Background:

• Acinetobacter baumannii is a critical global pathogen known for acquiring antibiotic resistance.
• Type IV pili (T4P) are essential for A. baumannii motility, biofilm formation, and host cell adhesion.
• The PilA protein, a component of T4P, represents a potential therapeutic target for combating A. baumannii virulence.

Purpose of the Study:

• To identify and develop novel drug molecules that target PilA in A. baumannii.
• To mitigate the virulence of A. baumannii by inhibiting T4P-mediated processes.
• To discover potential therapeutic agents against antibiotic-resistant strains of A. baumannii.

Main Methods:

• High-throughput virtual screening of over 60,000 compounds from multiple databases using Schrodinger software.
• Docking studies in extra precision (XP) mode to identify top-ranking compounds.
• Molecular dynamics (MD) simulations and Molecular Mechanics Poisson-Boltzmann Surface Area (MMPBSA) analysis to assess the stability and binding affinity of PilA-ligand complexes.

Main Results:

• Six lead compounds were identified from virtual screening, with docking scores ranging from -5.0 to -7.5 kcal/mol.
• Molecular dynamics simulations confirmed the structural stability of PilA-ligand complexes.
• The PilA-N098-0051 complex demonstrated enhanced stability and robust binding interactions, highlighting its therapeutic potential.

Conclusions:

• The identified compounds, particularly N098-0051, show significant promise as novel therapeutic agents targeting PilA in A. baumannii.
• These findings warrant further in vitro and in vivo validation to confirm the efficacy of N098-0051 against A. baumannii infections.
• Targeting PilA offers a potential strategy to overcome antibiotic resistance in A. baumannii.