title: Macromolecular crowding and protein stability.
abstract: An understanding of cellular chemistry requires knowledge of how crowded environments affect proteins. The influence of crowding on protein stability arises from two phenomena, hard-core repulsions and soft (i.e., chemical) interactions. Most efforts to understand crowding effects on protein stability, however, focus on hard-core repulsions, which are inherently entropic and stabilizing. We assessed these phenomena by measuring the temperature dependence of NMR-detected amide proton exchange and used these data to extract the entropic and enthalpic contributions of crowding to the stability of ubiquitin. Contrary to expectations, the contribution of chemical interactions is large and in many cases dominates the contribution from hardcore repulsions. Our results show that both chemical interactions and hard-core repulsions must be considered when assessing the effects of crowding and help explain previous observations about protein stability and dynamics in cells.
authors.affiliation: Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599, USA.
authors.forename: Yaqiang
authors.initials: Y
authors.lastname: Wang
authors.forename: Mohona
authors.initials: M
authors.lastname: Sarkar
authors.forename: Austin E
authors.initials: AE
authors.lastname: Smith
authors.forename: Alexander S
authors.initials: AS
authors.lastname: Krois
authors.forename: Gary J
authors.initials: GJ
authors.lastname: Pielak
mesh_terms: D000818:Animals; D005362:Ficoll / Q000737:chemistry; D006801:Humans; D046911:Macromolecular Substances / Q000737:chemistry*; D009113:Muramidase / Q000737:chemistry; D011205:Povidone / Q000737:chemistry; D055550:Protein Stability; D011506:Proteins / Q000737:chemistry*; D012710:Serum Albumin, Bovine / Q000737:chemistry; D013816:Thermodynamics; D025801:Ubiquitin / Q000737:chemistry
chemical_list: D046911:Macromolecular Substances; D011506:Proteins; D025801:Ubiquitin; D005362:Ficoll; D012710:Serum Albumin, Bovine; D009113:Muramidase; D011205:Povidone