Mapping the Binding Site of a Large Set of Quinazoline Type EGF‐R Inhibitors Using Molecular Field Analyses and Molecular Docking Studies.

Abstract

In the current work, three-dimensional QSAR studies for one large set of quinazoline type epidermal growth factor receptor (EGF-R) inhibitors were conducted using two types of molecular field analysis techniques: comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA). These compounds belonging to six different structural classes were randomly divided into a training set of 122 compounds and a test set of 13 compounds. The statistical results showed that the 3D-QSAR models derived from CoMFA were superior to those generated from CoMSIA. The most optimal CoMFA model after region focusing bears significant cross-validated r 2 cv of 0.60 and conventional r 2 of 0.92. The predictive power of the best CoMFA model was further validated by the accurate estimation to these compounds in the external test set, and the mean agreement of experimental and predicted log(IC 50 ) values of the inhibitors is 0.6 log unit. Separate CoMFA models were conducted to evaluate the influence of different partial charges (Gasteiger-Marsili, Gasteiger-Hückel, MMFF94, ESP-AM1, and MPA-AM1) on the statistical quality of the models. The resulting CoMFA field map provides information on the geometry of the binding site cavity and the relative weights of various properties in different site pockets for each of the substrates considered. Moreover, in the current work, we applied MD simulations combined with MM/ PBSA (Molecular mechanics/Possion-Boltzmann Surface Area) to determine the correct binding mode of the best inhibitor for which no ligand-protein crystal structure was present. To proceed, we define the following procedure: three hundred picosecond molecular dynamics simulations were first performed for the four binding modes suggested by DOCK 4.0 and manual docking, and then MM/PBSA was carried out for the collected snapshots. The most favorable binding mode identified by MM/PBSA has a binding free energy about 10 kcal/mol more favorable than the second best one. The most favorable binding mode identified by MM/PBSA can give satisfactory explanation of the SAR data of the studied molecules and is in good agreement with the contour maps of CoMFA. The most favorable binding mode suggests that with the quinazoline-based inhibitor, the N3 atom is hydrogen-bonded to a water molecule which, in turn, interacts with Thr 766, not Thr 830 as proposed by Wissner et al. (J. Med. Chem. 2000, 43, 3244). The predicted complex structure of quinazoline type inhibitor with EGF-R as well as the pharmacophore mapping from CoMFA can interpret the structure activities of the inhibitors well and afford us important information for structure-based drug design.

Quantitative Prediction of Fold Resistance for Inhibitors of EGFR

“…Prior computational studies of this system have included use of homology and molecular modeling (33), comparative molecular field analysis (CoMFA) (34), virtual screening (35), and molecular dynamics (33, 34, 36, 37). Use of MM-PBSA methods, similar in principle to the calculations employed in the present manuscript, were reported by Hou et al (34) for refinement of docked ligand poses, and by Liu et al (36) to study the impact of point mutations on binding for gefitinib. Surprisingly, there have been few all-atom molecular dynamics studies reporting quantitative binding energy comparisons between theory and experiment for ligands with EGFR.…”

Insight into the selective mechanism of phosphoinositide 3‐kinase γ with benzothiazole and thiazolopiperidine γ‐specific inhibitors by in silico approaches

“…The binding free energy (∆ G bind ) for each system was calculated by the Molecular Mechanics/Generalized Born Surface Area (MM/GBSA) methodology in AMBER according to the Equation :(Chen et al., , ; Genheden & Ryde, ; Gohlke, Kiel, & Case, ; Hou, Li, & Wang, ; Hou, Wang, Li, & Wang, ,; Hou, Zhu, Chen, & Xu, ; Liu, Yao, Wang, & Han, ; Pan et al., ; Sun, Li, Li, & Hou, ; Sun et al., ; Sun, Li, Shen, et al., ; Sun, Li, Tian, et al., ; Xu, Li, Li, Zhou, & Hou, ; Xu, Sun, Li, Wang, & Hou, ; Xue et al., ; Xue, Qi, et al., ; Xue, Wang, et al., ; Yang, Shen, Liu, & Yao, ; Yang et al., ; Zhang, Hou, Wang, & Liu, ) where ∆ E MM is the gas‐phase interaction energy between protein and ligand, consisting of electrostatic (∆ E ele ) and VDW interactions (∆ E vdw ). The polar and non‐polar contributions of the solvation free energy represented by ∆ G GB and ∆ G SA .…”

EVOLUTIONAL AND FUNCTIONAL ANALYSIS OF A SERINE PROTEASE IN Spodoptera litura

“…Molecular Mechanic/Poisson-Boltzmann Surface Area (MM-PBSA; (Kollman et al, 2000;Wang et al, 2001;Hou et al, 2003) was used to calculate the binding free energy of the…”