title: Unusual cold denaturation of a small protein domain.
abstract: A thermal unfolding study of the 45-residue α-helical domain UBA(2) using circular dichroism is presented. The protein is highly thermostable and exhibits a clear cold unfolding transition with the onset near 290 K without denaturant. Cold denaturation in proteins is rarely observed in general and is quite unique among small helical protein domains. The cold unfolding was further investigated in urea solutions, and a simple thermodynamic model was used to fit all thermal and urea unfolding data. The resulting thermodynamic parameters are compared to those of other small protein domains. Possible origins of the unusual cold unfolding of UBA(2) are discussed.
authors.affiliation: Department of Chemistry, University of Wyoming, 1000 E University Ave, Laramie, WY 82071, USA.
authors.forename: Ginka S
authors.initials: GS
authors.lastname: Buchner
authors.forename: Natalie
authors.initials: N
authors.lastname: Shih
authors.forename: Amy E
authors.initials: AE
authors.lastname: Reece
authors.forename: Stephan
authors.initials: S
authors.lastname: Niebling
authors.forename: Jan
authors.initials: J
authors.lastname: Kubelka
mesh_terms: D002942:Circular Dichroism; D003080:Cold Temperature; D045643:DNA Repair Enzymes / Q000737:chemistry*; D004268:DNA-Binding Proteins / Q000737:chemistry*; D011489:Protein Denaturation; D055550:Protein Stability; D017434:Protein Structure, Tertiary; D058767:Protein Unfolding; D013816:Thermodynamics
chemical_list: D004268:DNA-Binding Proteins; C086985:RAD23A protein, human; D045643:DNA Repair Enzymes