title: Adaptation of Extremophilic Proteins with Temperature and Pressure: Evidence from Initiation Factor 6.
abstract: In this work, we study dynamical properties of an extremophilic protein, Initiation Factor 6 (IF6), produced by the archeabacterium Methanocaldococcus jannascii, which thrives close to deep-sea hydrothermal vents where temperatures reach 80 °C and the pressure is up to 750 bar. Molecular dynamics simulations (MD) and quasi-elastic neutron scattering (QENS) measurements give new insights into the dynamical properties of this protein with respect to its eukaryotic and mesophilic homologue. Results obtained by MD are supported by QENS data and are interpreted within the framework of a fractional Brownian dynamics model for the characterization of protein relaxation dynamics. IF6 from M. jannaschii at high temperature and pressure shares similar flexibility with its eukaryotic homologue from S. cerevisieae under ambient conditions. This work shows for the first time, to our knowledge, that the very common pattern of corresponding states for thermophilic protein adaptation can be extended to thermo-barophilic proteins. A detailed analysis of dynamic properties and of local structural fluctuations reveals a complex pattern for "corresponding" structural flexibilities. In particular, in the case of IF6, the latter seems to be strongly related to the entropic contribution given by an additional, C-terminal, 20 amino-acid tail which is evolutionary conserved in all mesophilic IF6s.
authors.affiliation: †SISSA, International School for Advanced Studies, via Bonomea 265, 34136 Trieste, Italy.
authors.forename: Paolo A
authors.initials: PA
authors.lastname: Calligari
authors.affiliation: ‡Computational Biophysics, German Research School for Simulation Sciences, Jülich, Germany.
authors.forename: Vania
authors.initials: V
authors.lastname: Calandrini
authors.affiliation: §Institut Laue-Langevin, 6 Rue Jules Horowitz, BP 156, 38042 Grenoble Cedex, France.
authors.forename: Jacques
authors.initials: J
authors.lastname: Ollivier
authors.affiliation: §Institut Laue-Langevin, 6 Rue Jules Horowitz, BP 156, 38042 Grenoble Cedex, France.
authors.forename: Jean-Baptiste
authors.initials: JB
authors.lastname: Artero
authors.affiliation: §Institut Laue-Langevin, 6 Rue Jules Horowitz, BP 156, 38042 Grenoble Cedex, France.
authors.forename: Michael
authors.initials: M
authors.lastname: Härtlein
authors.affiliation: §Institut Laue-Langevin, 6 Rue Jules Horowitz, BP 156, 38042 Grenoble Cedex, France.
authors.forename: Mark
authors.initials: M
authors.lastname: Johnson
authors.affiliation: ∥Centre de Biophysique Moléculaire, CNRS UPR 4301, Rue Charles Sadron, F-45071 Orléans Cedex 2, France.|⊥Synchrotron Soleil, L'Orme de Merisiers, BP 48, 91192 Gif-sur-Yvette, France.|#Université de Orléans, Chateau de la Source-Av. du Parc Floral, 45067 Orléans, France.
authors.forename: Gerald R
authors.initials: GR
authors.lastname: Kneller
mesh_terms: D019843:Archaeal Proteins / Q000737:chemistry*; D057446:Hydrodynamics; D063747:Methanocaldococcus; D056004:Molecular Dynamics Simulation; D033363:Neutron Diffraction; D018583:Pliability; D011312:Pressure; D039662:Prokaryotic Initiation Factors / Q000737:chemistry*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry; D013696:Temperature
chemical_list: D019843:Archaeal Proteins; D039662:Prokaryotic Initiation Factors; D029701:Saccharomyces cerevisiae Proteins