Domain 3 of NS5A Protein from the Hepatitis C Virus Has Intrinsic α-Helical Propensity and Is a Substrate of Cyclophilin A

• DOI: 10.1074/jbc.m110.182436
• Publication Date: 2011-04-14T00:17:01Z
• Authors: Dries Verdegem; Aurélie Badillo; Jean-Michel Wieru...; Isabelle Landrieu; Arnaud Leroy; Ralf Bartenschlager; François Penin; Guy Lippens; Xavier Hanoulle
• Keywords: Cypa; NS5A; Cyclophilin; Prolyl isomerase; Daclatasvir

Nonstructural protein 5A (NS5A) is essential for hepatitis C virus (HCV) replication and constitutes an attractive target antiviral drug development. Although structural data its in-plane membrane anchor domain D1 are available, the structure of domains 2 (D2) 3 (D3) remain poorly defined. We report here a comparative molecular characterization NS5A-D3 HCV JFH-1 (genotype 2a) Con1 1b) strains. Combining gel filtration, CD, NMR spectroscopy analyses, we show that natively unfolded. However, from both strains exhibit propensity to partially fold into α-helix. analysis identifies two putative α-helices, which model could be obtained. The amphipathic nature first helix conservation in all genotypes suggest it might correspond recognition element and, as such, promote interaction with relevant biological partner(s). Because mutations conferring resistance cyclophilin inhibitors have been mapped NS5A-D3, also investigated functional between A (CypA). CypA indeed interacts this completely abolished by cyclosporin A. heteronuclear exchange experiments demonstrate has vitro peptidyl-prolyl cis/trans-isomerase activity toward some, but not all, bonds NS5A-D3. These studies lead novel insights features relationships CypA.