title: Insights into the Hendra virus NTAIL-XD complex: Evidence for a parallel organization of the helical MoRE at the XD surface stabilized by a combination of hydrophobic and polar interactions.
abstract: The Hendra virus is a member of the Henipavirus genus within the Paramyxoviridae family. The nucleoprotein, which consists of a structured core and of a C-terminal intrinsically disordered domain (N(TAIL)), encapsidates the viral genome within a helical nucleocapsid. N(TAIL) partly protrudes from the surface of the nucleocapsid being thus capable of interacting with the C-terminal X domain (XD) of the viral phosphoprotein. Interaction with XD implies a molecular recognition element (MoRE) that is located within N(TAIL) residues 470-490, and that undergoes α-helical folding. The MoRE has been proposed to be embedded in the hydrophobic groove delimited by helices α2 and α3 of XD, although experimental data could not discriminate between a parallel and an antiparallel orientation of the MoRE. Previous studies also showed that if the binding interface is enriched in hydrophobic residues, charged residues located close to the interface might play a role in complex formation. Here, we targeted for site directed mutagenesis two acidic and two basic residues within XD and N(TAIL). ITC studies showed that electrostatics plays a crucial role in complex formation and pointed a parallel orientation of the MoRE as more likely. Further support for a parallel orientation was afforded by SAXS studies that made use of two chimeric constructs in which XD and the MoRE were covalently linked to each other. Altogether, these studies unveiled the multiparametric nature of the interactions established within this complex and contribute to shed light onto the molecular features of protein interfaces involving intrinsically disordered regions.
authors.affiliation: Aix-Marseille University, Architecture et Fonction des Macromolécules Biologiques (AFMB) UMR 7257, 13288, Marseille, France; CNRS, AFMB UMR 7257, 13288, Marseille, France.
authors.forename: Jenny
authors.initials: J
authors.lastname: Erales
authors.affiliation: Aix-Marseille University, Architecture et Fonction des Macromolécules Biologiques (AFMB) UMR 7257, 13288, Marseille, France; CNRS, AFMB UMR 7257, 13288, Marseille, France.
authors.forename: Matilde
authors.initials: M
authors.lastname: Beltrandi
authors.affiliation: Aix-Marseille University, Architecture et Fonction des Macromolécules Biologiques (AFMB) UMR 7257, 13288, Marseille, France; CNRS, AFMB UMR 7257, 13288, Marseille, France.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Roche
authors.affiliation: Aix-Marseille University, Architecture et Fonction des Macromolécules Biologiques (AFMB) UMR 7257, 13288, Marseille, France; CNRS, AFMB UMR 7257, 13288, Marseille, France.
authors.forename: Maria
authors.initials: M
authors.lastname: Maté
authors.affiliation: Aix-Marseille University, Architecture et Fonction des Macromolécules Biologiques (AFMB) UMR 7257, 13288, Marseille, France; CNRS, AFMB UMR 7257, 13288, Marseille, France. Electronic address: Sonia.Longhi@afmb.univ-mrs.fr.
authors.forename: Sonia
authors.initials: S
authors.lastname: Longhi
mesh_terms: D045404:Hendra Virus / Q000737:chemistry* / Q000235:genetics; D057927:Hydrophobic and Hydrophilic Interactions; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D019590:Nucleocapsid Proteins; D009698:Nucleoproteins / Q000737:chemistry* / Q000235:genetics; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D014764:Viral Proteins / Q000737:chemistry* / Q000235:genetics
chemical_list: D019590:Nucleocapsid Proteins; D009698:Nucleoproteins; D014764:Viral Proteins; C116067:nucleoprotein, Hendra virus
keywords: Binding affinity; Far-UV circular dichroism; Intrinsically disordered proteins; Isothermal titration calorimetry; Protein–protein interactions and interfaces; Small angle X-ray scattering