title: Intrinsic Disorder to Order Transitions in the Scaffold Phosphoprotein P from the Respiratory Syncytial Virus RNA Polymerase Complex.
abstract: Intrinsic disorder is at the center of biochemical regulation and is particularly overrepresented among the often multifunctional viral proteins. Replication and transcription of the respiratory syncytial virus (RSV) relies on a RNA polymerase complex with a phosphoprotein cofactor P as the structural scaffold, which consists of a four-helix bundle tetramerization domain flanked by two domains predicted to be intrinsically disordered. Because intrinsic disorder cannot be reduced to a defined atomic structure, we tackled the experimental dissection of the disorder-order transitions of P by a domain fragmentation approach. P remains as a tetramer above 70 °C but shows a pronounced reversible secondary structure transition between 10 and 60 °C. While the N-terminal module behaves as a random coil-like IDP in a manner independent of tetramerization, the isolated C-terminal module displays a cooperative and reversible metastable transition. When linked to the tetramerization domain, the C-terminal module becomes markedly more structured and stable, with strong ANS binding. Therefore, the tertiary structure in the C-terminal module is not compact, conferring "late" molten globule-like IDP properties, stabilized by interactions favored by tetramerization. The presence of a folded structure highly sensitive to temperature, reversibly and almost instantly formed and broken, suggests a temperature sensing activity. The marginal stability allows for exposure of protein binding sites, offering a thermodynamic and kinetic fine-tuning in order-disorder transitions, essential for the assembly and function of the RSV RNA polymerase complex.
authors.affiliation: Protein Structure-Function and Engineering Laboratory, Fundación Instituto Leloir and IIBBA-CONICET , Av. Patricias Argentinas 435, 1405 Buenos Aires, Argentina.
authors.forename: María G
authors.initials: MG
authors.lastname: Noval
authors.affiliation: Protein Structure-Function and Engineering Laboratory, Fundación Instituto Leloir and IIBBA-CONICET , Av. Patricias Argentinas 435, 1405 Buenos Aires, Argentina.
authors.forename: Sebastian A
authors.initials: SA
authors.lastname: Esperante
authors.affiliation: Protein Structure-Function and Engineering Laboratory, Fundación Instituto Leloir and IIBBA-CONICET , Av. Patricias Argentinas 435, 1405 Buenos Aires, Argentina.
authors.forename: Ivana G
authors.initials: IG
authors.lastname: Molina
authors.affiliation: Protein Structure-Function and Engineering Laboratory, Fundación Instituto Leloir and IIBBA-CONICET , Av. Patricias Argentinas 435, 1405 Buenos Aires, Argentina.
authors.forename: Lucía B
authors.initials: LB
authors.lastname: Chemes
authors.affiliation: Protein Structure-Function and Engineering Laboratory, Fundación Instituto Leloir and IIBBA-CONICET , Av. Patricias Argentinas 435, 1405 Buenos Aires, Argentina.|CNPq, Laboratório de Genômica Estrutural, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro , Rio de Janeiro, RJ, Brazil.
authors.forename: Gonzalo de
authors.initials: Gd
authors.lastname: Prat-Gay
mesh_terms: D012321:DNA-Directed RNA Polymerases / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D034521:Nuclear Matrix-Associated Proteins / Q000737:chemistry / Q000378:metabolism*; D010750:Phosphoproteins / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding / Q000502:physiology; D018113:Respiratory Syncytial Virus, Human / Q000737:chemistry / Q000378:metabolism*; D014764:Viral Proteins / Q000737:chemistry / Q000378:metabolism
chemical_list: D034521:Nuclear Matrix-Associated Proteins; D010750:Phosphoproteins; D014764:Viral Proteins; D012321:DNA-Directed RNA Polymerases