Use of Structure-And Ligand-Based Drug Design Tools for the Discovery of Small Molecule Inhibitors of Cysteine Proteases for the Treatment of Malaria and Sars Infection

A wide array of molecular modeling tools were utilized to design and develop inhibitors against cysteine protease of P. Falciparum Malaria and Severe Acute Respiratory Syndrome (SARS). A number of potent inhibitors were developed against cysteine protease and hemoglobinase of P. falciparum , referred as Falcipains (FPs), by the structure-based virtual screening of the focused libraries enriched in soft-electrophiles containing compounds. Twenty one diverse, non-peptidic, low micromolar hits were identified. A combined data mining and combinatorial library synthesis approach was performed to discover analogs of virtual screening hits and establish the structure-activity relationships (SAR). However, the resulting SAR of the identified hits was unusually steep in some cases and could not be explained by a traditional analysis of the interactions (electrostatics, van der Waals or H-bond). To gain insights, a statistical thermodynamic analysis of explicit solvent in the ligand binding domain of FP-2 and FP-3 was performed that explained some of the complex trends in the SAR. Furthermore, the moderate potency of a subset of FP-2 hits was elucidated using quantum mechanics calculations that shoreduced reactivity of the electrophilic center of these hits. In addition, solvent thermodynamics and reactivity analysis also helped to elucidate the complex trends in SAR of peptidomimetic inhibitors of FP-2 and FP-3 synthesized in our laboratory. Multi nanosecond explicit solvent molecular dynamics simulations were carried out using the docking poses of the known inhibitors in the binding site of SARS-3CLpro, a cysteine protease important for replication of SARS virus, to study the overall stability of the binding site interactions as well as identify important changes in the interaction profile that were not apparent from the docking study. Analysis of the simulation studies led to the identification of certain protein-ligand interaction patterns which would be useful in further structure based design efforts against cysteine protease (3CLpro) of SARS.

Name thesis:degree_name

Ph.D. in Pharmaceutical Sciences

Level thesis:degree_level

Dissertation

Year dc:date.available

2011

Author dc:creator

• Shah, Falgun

Contributors dc:contributor

• Stephen J. Cutler
• Robert J. Doerksen
• Babu L. Tekwani

• Chemical Reactivity
• Cysteine Protease
• Falcipain
• Solvent Thermodynamics
• Structure-Based Drug Design
• Virtual Screening
• Pharmacy and Pharmaceutical Sciences

Repository record dc:identifier

https://egrove.olemiss.edu/etd/260

OAI identifier oai:identifier

oai:egrove.olemiss.edu:etd-1259