title: Residue-level interrogation of macromolecular crowding effects on protein stability.
abstract: Theory predicts that macromolecular crowding affects protein behavior, but experimental confirmation is scant. Herein, we report the first residue-level interrogation of the effects of macromolecular crowding on protein stability. We observe up to a 100-fold increase in the stability, as measured by the equilibrium constant for folding, for the globular protein chymotrypsin inhibitor 2 (CI2) in concentrations of the cosolute poly(vinylpyrrolidone) (PVP) that mimic the protein concentration in cells. We show that the increased stability is caused by the polymeric nature of PVP and that the degree of stabilization depends on both the location of the individual residue in the protein structure and the PVP concentration. Our data reinforce the assertion that macromolecular crowding stabilizes the protein by destabilizing its unfolded states.
authors.affiliation: Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA.
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Charlton
authors.forename: Christopher O
authors.initials: CO
authors.lastname: Barnes
authors.forename: Conggang
authors.initials: C
authors.lastname: Li
authors.forename: Jillian
authors.initials: J
authors.lastname: Orans
authors.forename: Gregory B
authors.initials: GB
authors.lastname: Young
authors.forename: Gary J
authors.initials: GJ
authors.lastname: Pielak
mesh_terms: D007700:Kinetics; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D019906:Nuclear Magnetic Resonance, Biomolecular; D010455:Peptides / Q000737:chemistry*; D010940:Plant Proteins / Q000737:chemistry*; D011205:Povidone / Q000737:chemistry*; D011487:Protein Conformation; D017510:Protein Folding; D017433:Protein Structure, Secondary; D013329:Structure-Activity Relationship; D013816:Thermodynamics
chemical_list: D010455:Peptides; D010940:Plant Proteins; C093336:chymotrypsin inhibitor 2; D011205:Povidone