title: Thermodynamics of protein destabilization in live cells.
abstract: Although protein folding and stability have been well explored under simplified conditions in vitro, it is yet unclear how these basic self-organization events are modulated by the crowded interior of live cells. To find out, we use here in-cell NMR to follow at atomic resolution the thermal unfolding of a β-barrel protein inside mammalian and bacterial cells. Challenging the view from in vitro crowding effects, we find that the cells destabilize the protein at 37 °C but with a conspicuous twist: While the melting temperature goes down the cold unfolding moves into the physiological regime, coupled to an augmented heat-capacity change. The effect seems induced by transient, sequence-specific, interactions with the cellular components, acting preferentially on the unfolded ensemble. This points to a model where the in vivo influence on protein behavior is case specific, determined by the individual protein's interplay with the functionally optimized "interaction landscape" of the cellular interior.
authors.affiliation: Department of Biochemistry and Biophysics, Arrhenius Laboratories of Natural Sciences, Stockholm University, 10691 Stockholm, Sweden; mikael.oliveberg@dbb.su.se jens.danielsson@dbb.su.se.
authors.forename: Jens
authors.initials: J
authors.lastname: Danielsson
authors.affiliation: Department of Biochemistry and Biophysics, Arrhenius Laboratories of Natural Sciences, Stockholm University, 10691 Stockholm, Sweden;
authors.forename: Xin
authors.initials: X
authors.lastname: Mu
authors.affiliation: Department of Biochemistry and Biophysics, Arrhenius Laboratories of Natural Sciences, Stockholm University, 10691 Stockholm, Sweden;
authors.forename: Lisa
authors.initials: L
authors.lastname: Lang
authors.affiliation: Department of Biochemistry and Biophysics, Arrhenius Laboratories of Natural Sciences, Stockholm University, 10691 Stockholm, Sweden;
authors.forename: Huabing
authors.initials: H
authors.lastname: Wang
authors.affiliation: In-Cell Nuclear Magnetic Resonance (NMR) Laboratory, Department of NMR-Supported Structural Biology, Leibniz Institute of Molecular Pharmacology (FMP Berlin), 13125 Berlin, Germany;
authors.forename: Andres
authors.initials: A
authors.lastname: Binolfi
authors.affiliation: In-Cell Nuclear Magnetic Resonance (NMR) Laboratory, Department of NMR-Supported Structural Biology, Leibniz Institute of Molecular Pharmacology (FMP Berlin), 13125 Berlin, Germany;
authors.forename: François-Xavier
authors.initials: FX
authors.lastname: Theillet
authors.affiliation: In-Cell Nuclear Magnetic Resonance (NMR) Laboratory, Department of NMR-Supported Structural Biology, Leibniz Institute of Molecular Pharmacology (FMP Berlin), 13125 Berlin, Germany;
authors.forename: Beata
authors.initials: B
authors.lastname: Bekei
authors.affiliation: Division of Biochemistry and Structural Biology, Department of Chemistry, Lund University, 22100 Lund, Sweden;
authors.forename: Derek T
authors.initials: DT
authors.lastname: Logan
authors.affiliation: In-Cell Nuclear Magnetic Resonance (NMR) Laboratory, Department of NMR-Supported Structural Biology, Leibniz Institute of Molecular Pharmacology (FMP Berlin), 13125 Berlin, Germany;
authors.forename: Philipp
authors.initials: P
authors.lastname: Selenko
authors.affiliation: Division of Physical Chemistry, Department of Chemistry, Lund University, 22100 Lund, Sweden.
authors.forename: Håkan
authors.initials: H
authors.lastname: Wennerström
authors.affiliation: Department of Biochemistry and Biophysics, Arrhenius Laboratories of Natural Sciences, Stockholm University, 10691 Stockholm, Sweden; mikael.oliveberg@dbb.su.se jens.danielsson@dbb.su.se.
authors.forename: Mikael
authors.initials: M
authors.lastname: Oliveberg
mesh_terms: D000465:Algorithms; D000818:Animals; D020134:Catalytic Domain; D045744:Cell Line, Tumor; D002942:Circular Dichroism; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D051379:Mice; D008958:Models, Molecular; D017510:Protein Folding; D055550:Protein Stability; D017434:Protein Structure, Tertiary; D058767:Protein Unfolding; D011506:Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D013482:Superoxide Dismutase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D013696:Temperature; D013816:Thermodynamics
chemical_list: D011506:Proteins; D013482:Superoxide Dismutase
keywords: NMR; crowding; in vivo; protein stability; thermodynamics