Dengue Virus NS3 Serine Protease

Abstract

The mosquito-borne dengue viruses are widespread human pathogens causing dengue fever, dengue hemorrhagic fever, and dengue shock syndrome, placing 40% of the world's population at risk with no effective treatment. The viral genome is a positive strand RNA that encodes a single polyprotein precursor. Processing of the polyprotein precursor into mature proteins is carried out by the host signal peptidase and by NS3 serine protease, which requires NS2B as a cofactor. We report here the crystal structure of the NS3 serine protease domain at 2.1 Å resolution. This structure of the protease combined with modeling of peptide substrates into the active site suggests identities of residues involved in substrate recognition as well as providing a structural basis for several mutational effects on enzyme activity. This structure will be useful for development of specific inhibitors as therapeutics against dengue and other flaviviral proteases.

Enzymatic Characterization and Homology Model of a Catalytically Active Recombinant West Nile Virus NS3 Protease

“…Homology Modeling-West Nile Virus NS3 protease homology models were generated using the structures of the Dengue virus NS3 protease without ligand (pdb1BEF), (9) and with Bowman-Birk inhibitor (pdb1DF9, subunit B), (9) and hepatitis C virus NS3 protease with bound cofactor (pdb1A1Q) (8). Models were generated using the Modeler and the Homology module within the InsightII molecular modeling system (17).…”

“…Homology Modeling-In order to provide a structural basis for further investigations of the WNV protease, for which no current crystal structure exists, a homology structural model was generated based on the crystal structures of two flavivirus proteases, the Dengue virus NS3 protease (pdb1BEF and pdb1DF9) (9), and the hepatitis C virus NS3 protease (pdb1A1Q) (8). The Dengue virus NS3 and hepatitis C virus proteases were selected as a basis for the WNV protease model for their sequence homology (with Dengue NS3pro, Fig.…”

“…The remainder of NS2B encodes 3 hydrophobic domains, believed to be involved in membrane association and localization of the enzyme to convoluted membrane regions on the endoplasmic reticulum (7). The structure of WNV NS3 protease is unknown, but there are reported crystal structures for related NS3 proteases of hepatitis C virus (HCV) (8) and Dengue virus (DEN2) (9). The structure of the latter protease was however determined in the absence of the NS2B cofactor and was thus an inactive enzyme.…”

Site-directed Mutagenesis and Kinetic Studies of the West Nile Virus NS3 Protease Identify Key Enzyme-Substrate Interactions

“…The structure of the WNV NS3 protease is unknown, but there are reported crystal structures for related NS3 proteases of hepatitis C virus (HCV) with a cofactor (23) and Dengue-2 virus without NS2B cofactor (24). Therefore, the latter structure was of an inactive enzyme.…”

Fraud rocks protein community

“…two of Murthy's structures 1,3,4 were among 14 included in a virtual dengue drug-screening project run over the past year. This modelled how candidate molecules would interact with dengue proteins, using IBM's World Community Grid -a public computing network set up to harness unused computer time for projects of benefit to humanity.…”