abstract
Comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) based on three-dimensional quantitative structure- activity relationship (3D-QSAR) studies were conducted on a series (39 molecules) of peptidyl vinyl sulfone derivatives as potential Plasmodium Falciparum cysteine proteases inhibitors. Two different methods of alignment were employed: (i) a receptor-docked alignment derived from the structure-based docking algorithm GOLD and (ii) a ligand-based alignment using the structure of one of the ligands derived from a crystal structure from the PDB databank. The best predictions were obtained for the receptor-docked alignment with a CoMFA standard model (q(2) = 0.696 and r(2) = 0.980) and with CoMSIA combined electrostatic, and hydrophobic fields (q(2) = 0.711 and r(2) = 0.992). Both models were validated by a test set of nine compounds and gave satisfactory predictive r(2) pred values of 0.76 and 0.74, respectively. CoMFA and CoMSIA contour maps were used to identify critical regions where any change in the steric, electrostatic, and hydrophobic fields may affect the inhibitory activity, and to highlight the key structural features required for biological activity. Moreover, the results obtained from 3D-QSAR analyses were superimposed on the Plasmodium Falciparum cysteine proteases active site and the main interactions were studied. The present work provides extremely useful guidelines for future structural modifications of this class of compounds towards the development of superior antimalarials.
keywords
MALARIA PARASITES; GENETIC ALGORITHM; DRUG TARGETS; FIELD; CHLOROQUINE; RESISTANCE
subject category
Biochemistry & Molecular Biology; Biophysics; Computer Science
authors
Teixeira, C; Gomes, JRB; Couesnon, T; Gomes, P
our authors
acknowledgements
We are grateful for the financial support from Fundacao para a Ciencia e a Tecnologia (FCT, Portugal) to CIQ-UP and CICECO, for the Program Ciencia 2007 and for the Post-doctoral fellowship SFRH/BPD/62967/2009 awarded to Catia Teixeira. We also thank FCT and the European Union (FEDER) for funding through Project refs. PTDC/QUI/65142/2006 and FCOMP-01-0124-FEDER-007418, respectively.