title: Structural determinants for membrane association and dynamic organization of the hepatitis C virus NS3-4A complex.
abstract: Hepatitis C virus (HCV) NS3-4A is a membrane-associated multifunctional protein harboring serine protease and RNA helicase activities. It is an essential component of the HCV replication complex and a prime target for antiviral intervention. Here, we show that membrane association and structural organization of HCV NS3-4A are ensured in a cooperative manner by two membrane-binding determinants. We demonstrate that the N-terminal 21 amino acids of NS4A form a transmembrane alpha-helix that may be involved in intramembrane protein-protein interactions important for the assembly of a functional replication complex. In addition, we demonstrate that amphipathic helix alpha(0), formed by NS3 residues 12-23, serves as a second essential determinant for membrane association of NS3-4A, allowing proper positioning of the serine protease active site on the membrane. These results allowed us to propose a dynamic model for the membrane association, processing, and structural organization of NS3-4A on the membrane. This model has implications for the functional architecture of the HCV replication complex, proteolytic targeting of host factors, and drug design.
authors.affiliation: Department of Medicine II, University of Freiburg, D-79106 Freiburg, Germany.
authors.forename: Volker
authors.initials: V
authors.lastname: Brass
authors.forename: Jan Martin
authors.initials: JM
authors.lastname: Berke
authors.forename: Roland
authors.initials: R
authors.lastname: Montserret
authors.forename: Hubert E
authors.initials: HE
authors.lastname: Blum
authors.forename: François
authors.initials: F
authors.lastname: Penin
authors.forename: Darius
authors.initials: D
authors.lastname: Moradpour
mesh_terms: D000595:Amino Acid Sequence; D002352:Carrier Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D004252:DNA Mutational Analysis; D016174:Hepacivirus / Q000737:chemistry / Q000201:enzymology / Q000378:metabolism*; D047908:Intracellular Signaling Peptides and Proteins; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D014763:Viral Matrix Proteins / Q000737:chemistry / Q000378:metabolism; D017361:Viral Nonstructural Proteins / Q000737:chemistry* / Q000378:metabolism*; D014764:Viral Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D012697:Serine Endopeptidases; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases
chemical_list: D002352:Carrier Proteins; D047908:Intracellular Signaling Peptides and Proteins; D014763:Viral Matrix Proteins; D017361:Viral Nonstructural Proteins; D014764:Viral Proteins; C084422:NS3 protein, hepatitis C virus; D012697:Serine Endopeptidases; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases; C455041:NS4A cofactor peptide, Hepatitis C virus
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