MOLECULAR DOCKING-BASED EVALUATION OF GC–MS IDENTIFIED BIOACTIVE METABOLITES FROM BACILLUS PARAMYCOIDES ISOLATED FROM SEAWEED AGAINST ESSENTIAL ANTIBACTERIAL TARGETS

Abstract

Antimicrobial resistance has forced the search for new antibacterial agents from microbial sources. In this study, the bioactive secondary metabolites of Bacillus paramycoides  were characterized by Gas Chromatography–Mass Spectrometry (GC–MS), and their binding affinity was assessed by molecular docking analysis. GC–MS profiling revealed a wide variety of metabolites including fatty acids, terpenoids, phenolic compounds, sterols, and fatty acid amides. Of these, 2,6-dihydroxybenzaldehyde, palmitic acid, and phytol were selected for in silico study, and molecular docking was performed against two key antibacterial targets of Escherichia coli, UDP-N-acetylmuramoyl-tripeptide:D alanyl-D-alanine ligase (MurF; PDB ID: 1GG4) in peptidoglycan biosynthesis and DNA gyrase B (PDB ID: 4DUH) in DNA replication. Binding affinities ranged from -5.2 to -7.7 kcal/mol. 2,6-dihydroxybenzaldehyde showed the highest interaction with MurF (-6.3 kcal/mol), and phytol showed the highest interaction with DNA gyrase B (-7.7 kcal/mol), which suggests the antibacterial activity of these metabolites through inhibition of bacterial cell wall synthesis and DNA replication. The results of this study identify Bacillus paramycoides  as a potential source of bioactive metabolites and shed molecular light on their putative antibacterial mechanisms.