ABSTRACT
Dengue virus (DENV) belongs to the family Flaviviridae and can cause major health problems worldwide, including dengue fever and dengue shock syndrome. DENV replicon in human cells inhibits interferon α and ß with the help of its non-structural proteins. Non-structural protein 5 (NS5) of DENV is responsible for the proteasome-mediated degradation of signal transducer and activator of transcription (STAT) 2 protein, which has been implicated in the development of resistance against interferon-mediated antiviral effect. This degradation of STAT2 primarily occurs with the help of E3 ubiquitin ligases. Seven in absentia homologue (SIAH) 2 is a host protein that can mediate the ubiquitination of proteins and is known for its interaction with NS5. In this study, comprehensive computational analysis was performed to characterize the protein-protein interactions between NS5, SIAH2, and STAT2 to gain insight into the residues and sites of interaction between these proteins. The objective of the study was to structurally characterize the NS5-STAT2, SIAH2-STAT2, and NS5-SIAH2 interactions along with the determination of the possible reaction pattern for the degradation of STAT2. Docking and physicochemical studies indicated that DENV NS5 may first interact with the host SIAH2, which can then proceed towards binding with STAT2 from the side of SIAH2. These implications are reported for the first time and require validation by wet-lab studies.
Subject(s)
Dengue Virus/pathogenicity , Dengue/pathology , Nuclear Proteins/metabolism , STAT2 Transcription Factor/metabolism , Ubiquitin-Protein Ligases/metabolism , Viral Nonstructural Proteins/metabolism , Amino Acid Sequence , Dengue/immunology , Dengue Virus/immunology , Humans , Hydrophobic and Hydrophilic Interactions , Interferon Type I/antagonists & inhibitors , Interferon Type I/immunology , Models, Molecular , Molecular Docking Simulation , Nuclear Proteins/ultrastructure , Protein Interaction Maps , Protein Structure, Secondary , STAT1 Transcription Factor/metabolism , STAT1 Transcription Factor/ultrastructure , STAT2 Transcription Factor/ultrastructure , Sequence Alignment , Signal Transduction/immunology , Static Electricity , Ubiquitin-Protein Ligases/ultrastructure , Ubiquitination , Viral Nonstructural Proteins/ultrastructureABSTRACT
Three CYP6Z genes are linked to a major pyrethroid resistance locus in the mosquito Anopheles gambiae. We have expressed CYP6Z2 in Escherichia coli and produced a structural model in order to examine its role in detoxification. E. coli membranes co-expressing CYP6Z2 and An. gambiae P450 reductase (AgCPR) catalysed the dealkylation of benzyloxyresorufin with kinetic parameters K(m) = 0.13 microM; K(cat) = 1.5 min(-1). The IC(50) values of a wide range of compounds were measured. Pyrethroids cypermethrin and permethrin produced low IC(50) values, but were not metabolized. Plant flavanoids were the most potent inhibitors. Several compounds were shown to be substrates, suggesting that CYP6Z2 has broad substrate specificity and plays an important chemo-protective role during the herbivorous phase of the life-cycle.