Significance of catalase-peroxidase (KatG) mutations in mediating isoniazid resistance in clinical strains of Mycobacterium tuberculosis

•Clinical importance of five KatG mutants (MTs) leading to isoniazid (INH) resistance was investigated in silico.•Binding affinity based on docking was found to be higher for MTs than for wild-type (WT) (except MT-S315R).•Molecular dynamics (MD) analysis showed that fluctuations/deviations were larger at INH binding residues for MTs than WT.•Reduction in H-bond network after MD in all KatG enzymes implies increased flexibility/stability of protein structures.•Five MTs affect activity differently, attributed to conformational changes in KatG resulting in altered binding affinity.