EXPLORING HYDROPHOBIC BINDING SURFACES USING COMFA AND FLEXIBLE HYDROPHOBIC LIGANDS

摘要

Cysteine proteinases are a very important group of enzymes involved in a variety of physiological and pathological processes including cancer metastasis and rheumatoid arthritis. In this investigation we used 3D-Quantitative Structure Activity Relationships (3D-QSAR) techniques to model the binding of a variety of substrates to two cysteine proteinases, papain, and cathepsin B. The analysis was performed using Comparative Molecular Field Analysis (CoMFA). The molecules were constructed using standard bond angles and lengths, minimized and aligned. Charges were calculated using the PM3 method in MOPAC. The CoMFA models derived for the binding of the studied substrates to the two proteinases were compared with the expected results from the experimental X-ray crystal structures of the same proteinases. The results showed the value of CoMFA modeling of flexible hydrophobic ligands to analyze ligand binding to protein receptors, and could also serve as the basis to design specific inhibitors of cysteine proteinases with potential therapeutic value.