title: Protein stability at negative pressure.
abstract: We record proton NMR spectra of the protein ubiquitin at 1 atmosphere pressure and at negative pressures (under tension), under conditions where the native and denatured states are nearly equally populated. Analysis of the unique histidine aromatic resonance of ubiquitin shows that negative pressure destabilizes the protein, in accord with a quadratic free energy dependence on pressure and temperature previously suggested in the literature. Our molecular dynamics simulations at negative pressure agree with the experimental result. In addition, molecular dynamics predicts a turnaround of the folding free energy at very low pressure. An 'island of stability' may exist at very negative pressures, where the protein is likely to fold into low density fluctuations of the solvent.
authors.affiliation: Department of Physics, University of Illinois at Urbana-Champaign, IL 61801, USA.
authors.forename: Edgar
authors.initials: E
authors.lastname: Larios
authors.forename: Martin
authors.initials: M
authors.lastname: Gruebele
mesh_terms: D056004:Molecular Dynamics Simulation; D019906:Nuclear Magnetic Resonance, Biomolecular; D011312:Pressure; D011489:Protein Denaturation; D055550:Protein Stability; D058767:Protein Unfolding; D011506:Proteins / Q000737:chemistry; D025801:Ubiquitin / Q000737:chemistry
chemical_list: D011506:Proteins; D025801:Ubiquitin