title: High solubility supports efficient refolding of thermally unfolded β-lactamase.
abstract: Fusion technology is widely used to enhance soluble expression of recombinant proteins. We have shown before that halophilic β-lactamase (BLA) is an ideal candidate as a fusion partner. Here we have examined its thermal unfolding and refolding as a function of salt concentration. The thermal stability significantly increased as the salt concentration was increased from 0.2 to 1.84 M. Conversely, while reversibility of thermal unfolding was high at least up to 0.65 M salt, it was largely lost at 1.84 M. This was due to aggregation of thermally unfolded BLA. The addition of 3M urea suppressed aggregation, which in turn resulted in restoration of reversible refolding of heat-denatured protein.
authors.affiliation: Alliance Protein Laboratories, 3957 Corte Cancion, Thousand Oaks, CA 91360, USA. Tarakawa2@aol.com
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Arakawa
authors.forename: Hiroko
authors.initials: H
authors.lastname: Tokunaga
authors.forename: Rui
authors.initials: R
authors.lastname: Yamaguchi
authors.forename: Masao
authors.initials: M
authors.lastname: Tokunaga
mesh_terms: D002942:Circular Dichroism; D007700:Kinetics; D011489:Protein Denaturation / Q000187:drug effects; D058849:Protein Refolding / Q000187:drug effects; D058767:Protein Unfolding / Q000187:drug effects; D012965:Sodium Chloride / Q000494:pharmacology; D012995:Solubility / Q000187:drug effects; D013696:Temperature; D014508:Urea / Q000494:pharmacology; D001618:beta-Lactamases / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D012965:Sodium Chloride; D014508:Urea; D001618:beta-Lactamases