Figure 1: (A) Overall structure of CAIX is shown in cartoon model. The active site residues interacts with inhibitors are shown in sticks. The lower hydrophobic domain of active site is describe with Leu-91, Leu-93, Leu-198, Val-121, Leu135, while upper hydrophobic region constituted with Leu-141, Val-143, Pro-201, Pro-202. The amino acid residues, Trp-5, Trp-209 and Phe-245 are involved in ring aromatic interaction. His-96 and His-119 are defined as HBD. HBA feature was described as Glu-106, Thr-199 and Thr-200, His-94 and His-96. The centrally coordinated zinc atom (Zn+2) is shown in red sphere, may acts as positive ionisable/HBD feature. The negative ionisable feature is represented by Asp-132. Interacting features of active site residues are exported to LigandScout 3.1 was used for generation of CAIX inhibitor pharmacophore model. Structure was drawn in PyMol using atomic coordinates of PDB 3IAI [6]. (B) Docked pose of CAIX inhibitor acetazolamide (AAZ), represented in stick model. The active site residues, Gln-92, His-94, His-119, Thr-199 and Thr-200 are involved in polar interactions are illustrated in stick model. Leu- 198, Val-121, 131, 143 and Trp-209 are involved in hydrophobic and aromatic interactions, respectively. Polar interaction showed in black dotted line.