Structural and functional significance of the highly-conserved residues in Mycobacterium tuberculosis acetohydroxyacid synthase.

•Role of highly conserved His84, Glu85, and Gln86 of M. tuberculosis AHAS was evaluated.•These conserved residues are located in the ThDP binding pocket of AHAS.•Our study validates Glu85 plays a key catalytic function in M. tuberculosis AHAS.•Further, we suggest conserved His84 and Gln86 play a key supporting role in catalysis.