Consensus superiority of the pharmacophore-based alignment, over maximum common substructure (MCS): 3D-QSAR studies on carbamates as acetylcholinesterase inhibitors

J Chem Inf Model. 2009 Jun;49(6):1590-601. doi: 10.1021/ci900049e.

Abstract

In view of the nonavailability of complete X-ray structure of carbamates cocrystallized with AChE enzyme, the 3D-QSAR model development based on cocrystallized conformer (CCBA) as well as docked conformer-based alignment (DCBA) is not feasible. Therefore, the only two alternatives viz. pharmacophore and maximum common substructure-based alignments are left for the 3D-QSAR comparative molecular field analyses (CoMFA) and comparative molecular similarity indices analyses (CoMSIA) model development. So, in the present study, the 3D-QSAR models have been developed using both alignment methods, where CoMFA and CoMSIA models based on pharmacophore-based alignment were in good agreement with each other and demonstrated significant superiority over MCS-based alignment in terms of leave-one-out (LOO) cross-validated q(2) values of 0.573 and 0.723 and the r(2) values of 0.972 and 0.950, respectively. The validation of the best CoMFA and CoMSIA models based on pharmacophore (Hip-Hop)-based alignment on a test set of 17 compounds provided significant predictive r(2) [r(2)(pred(test))] of 0.614 and 0.788, respectively. The contour map analyses revealed the relative importance of steric, electrostatic, and hydrophobicity for AChE inhibition activity. However, hydrophobic factor plays a major contribution to the AChE inhibitory activity modulation which is in strong agreement with the fact that the AChE is having a wide active site gorge (approximately 20 A) occupied by a large number of hydrophobic amino acid residues.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylcholinesterase / metabolism*
  • Carbamates / chemistry*
  • Carbamates / pharmacology*
  • Cholinesterase Inhibitors / chemistry*
  • Cholinesterase Inhibitors / pharmacology*
  • Hydrophobic and Hydrophilic Interactions
  • Inhibitory Concentration 50
  • Models, Molecular
  • Molecular Conformation
  • Quantitative Structure-Activity Relationship*
  • Static Electricity

Substances

  • Carbamates
  • Cholinesterase Inhibitors
  • Acetylcholinesterase