title: The Disordered Region of the HCV Protein NS5A: Conformational Dynamics, SH3 Binding, and Phosphorylation.
abstract: Intrinsically disordered proteins (IDPs) perform their physiological role without possessing a well-defined three-dimensional structure. Still, residual structure and conformational dynamics of IDPs are crucial for the mechanisms underlying their functions. For example, regions of transient secondary structure are often involved in molecular recognition, with the structure being stabilized (or not) upon binding. Long-range interactions, on the other hand, determine the hydrodynamic radius of the IDP, and thus the distance over which the protein can catch binding partners via so-called fly-casting mechanisms. The modulation of long-range interactions also presents a convenient way of fine-tuning the protein's interaction network, by making binding sites more or less accessible. Here we studied, mainly by nuclear magnetic resonance spectroscopy, residual secondary structure and long-range interactions in nonstructural protein 5A (NS5A) from hepatitis C virus (HCV), a typical viral IDP with multiple functions during the viral life cycle. NS5A comprises an N-terminal folded domain, followed by a large (∼250-residue) disordered C-terminal part. Comparing nuclear magnetic resonance spectra of full-length NS5A with those of a protein construct composed of only the C-terminal residues 191-447 (NS5A-D2D3) allowed us to conclude that there is no significant interaction between the globular and disordered parts of NS5A. NS5A-D2D3, despite its overall high flexibility, shows a large extent of local residual (α-helical and β-turn) structure, as well as a network of electrostatic long-range interactions. Furthermore, we could demonstrate that these long-range interactions become modulated upon binding to the host protein Bin1, as well as after NS5A phosphorylation by CK2. As the charged peptide regions involved in these interactions are well conserved among the different HCV genotypes, these transient long-range interactions may be important for some of the functions of NS5A over the course of the HCV life cycle.
authors.affiliation: Institut de Biologie Structurale, Université Grenoble 1, Grenoble, France; Commissariat à l'Energie Atomique et aux Energies Alternatives, Grenoble, France; Centre National de Recherche Scientifique, Grenoble, France.
authors.forename: Zsófia
authors.initials: Z
authors.lastname: Sólyom
authors.affiliation: Institut de Biologie Structurale, Université Grenoble 1, Grenoble, France; Commissariat à l'Energie Atomique et aux Energies Alternatives, Grenoble, France; Centre National de Recherche Scientifique, Grenoble, France; Institute of Complex Systems-6 Structural Biochemistry, Forschungszentrum Jülich, Jülich, Germany.
authors.forename: Peixiang
authors.initials: P
authors.lastname: Ma
authors.affiliation: Institute of Complex Systems-6 Structural Biochemistry, Forschungszentrum Jülich, Jülich, Germany.
authors.forename: Melanie
authors.initials: M
authors.lastname: Schwarten
authors.affiliation: Institut des Biomolécules Max Mousseron, UMR 5247, Centre National de Recherche Scientifique, École Nationale Supérieure de Chimie de Montpellier, Université Montpellier, Montpellier, France; Equipe Chimie Bioorganique et Systèmes Amphiphiles, Avignon Université, Avignon, France.
authors.forename: Michaël
authors.initials: M
authors.lastname: Bosco
authors.affiliation: Institut des Biomolécules Max Mousseron, UMR 5247, Centre National de Recherche Scientifique, École Nationale Supérieure de Chimie de Montpellier, Université Montpellier, Montpellier, France; Equipe Chimie Bioorganique et Systèmes Amphiphiles, Avignon Université, Avignon, France.
authors.forename: Ange
authors.initials: A
authors.lastname: Polidori
authors.affiliation: Institut des Biomolécules Max Mousseron, UMR 5247, Centre National de Recherche Scientifique, École Nationale Supérieure de Chimie de Montpellier, Université Montpellier, Montpellier, France; Equipe Chimie Bioorganique et Systèmes Amphiphiles, Avignon Université, Avignon, France.
authors.forename: Grégory
authors.initials: G
authors.lastname: Durand
authors.affiliation: Commissariat à l'Energie Atomique et aux Energies Alternatives, Grenoble, France; Institute of Complex Systems-6 Structural Biochemistry, Forschungszentrum Jülich, Jülich, Germany; Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany.
authors.forename: Dieter
authors.initials: D
authors.lastname: Willbold
authors.affiliation: Institut de Biologie Structurale, Université Grenoble 1, Grenoble, France; Commissariat à l'Energie Atomique et aux Energies Alternatives, Grenoble, France; Centre National de Recherche Scientifique, Grenoble, France. Electronic address: bernhard.brutscher@ibs.fr.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Brutscher
mesh_terms: D001665:Binding Sites; D004926:Escherichia coli; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D010766:Phosphorylation; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D053838:Scattering, Small Angle; D055672:Static Electricity; D017361:Viral Nonstructural Proteins / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*; D014961:X-Ray Diffraction; D018909:src Homology Domains; D012324:RNA-Dependent RNA Polymerase
chemical_list: D011994:Recombinant Proteins; D017361:Viral Nonstructural Proteins; C087036:NS-5 protein, hepatitis C virus; D012324:RNA-Dependent RNA Polymerase