In silico Ligand-Based (LB) and Docking-Based (DB) 3D-QSAR Study of Potent Chk2 Inhibitors

Isothiazole carboxamidine compounds are potent ATP competitive Chk2 inhibitors. A series of compounds with Chk2 inhibitory activity were taken from literature and different 3D-QSAR models have been generated with Comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA). In first scheme LB-QSAR models were generated using fully optimized geometries by PM3 approach giving reasonable statistics of CoMFA (q2= 0.88, r
²
= 0.96 and r
²

_predictive
= 0.60) and CoMSIA(q
²
= 0.918 r
²
= 0.99 and r
<sup>2

predictive</sup>
= 0.55). In second and third scheme the ligands 7 docked in to receptor protein (PDB 2CN8). Consequently, two most plausible modes were identified and used as initial templates. The docked conformer based CoMFA model shows good correlation with activity (q
²
= 0.91, r
²
= 0.99 and r
²

_predictive
= 0.84). Whereas in CoMSIA, the steric and hydrophobic and donor field jointly give a better statistics (q
²
=0.92 r
²
= 0.99 and r
²

_predictive
=0.53). These findings might be helpful to design more potent Chk2 inhibitors.