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Establishment and application of high throughput screening model for hepatitis C virus NS3-4A protease inhibitors in vitro.

Research paper by Li L Jian-rui, Wu W Yan-bin, Si S Shu-yi, Chen C Hong-shan, Jiang J Jian-dong, Bang B Zong-gen

Indexed on: 08 Mar '11Published on: 08 Mar '11Published in: Zhongguo yi xue ke xue yuan xue bao. Acta Academiae Medicinae Sinicae



Abstract

To establish fluorescence resonance energy transfer (FRET) assay method of detecting proteolytic activity of non-structural protein 3-4A (NS3-4A) serine protease of hepatitis C virus (HCV) for high throughput screening inhibitors against HCV in vitro.HCV recombinant plasmid pMAL~c2/NS3-4A was transformed into the E.coli strain K12TB1. Maltose-binding-protein (MBP) NS3-4A fusion protein expression was induced by adding isopropyl-β-D-thiogalacto-pyranoside (IPTG) and purified by affinity chromatography. The proteolytic activity of MBP-NS3-4A protease was analyzed by FRET with the special protease substrate. The reaction system in this model was optimized, and the reliability of the model was evaluated.High throughput screening model for HCV NS3-4A protease inhibitors was established, and the best concentrations of enzyme and substrate were optimized. In the model, the Km value of protease was 4.74 μmol/L, Z factor was up to 0.80, and coefficient of variation (CV) was 1.91%. BILN 2061, one of the known HCV protease inhibitors, was measured with the Ki of 0.30 nmol/L.The assay model using FRET method for HCV NS3 4A serine protease is stable and reliable, and the model is suitable for high throughput screening for HCV NS3 4A protease inhibitors.