title: The effects of N-ethyl-N'-methyl imidazolium chloride on the solubility, stability and aggregation of tc-rPA.
abstract: The ionic liquid N-ethyl-N'-methyl imidazolium chloride (EMIMCl) has been described as being very efficient in promoting refolding of the recombinant plasminogen activator rPA. Our study reveals that molar concentrations of EMIMCl increase the solubility of native and unfolded proteins due to favorable interactions with amino acid side chains rather than favorably interacting with the peptide backbone. This delicate balance of favorable interactions with side chains and unfavorable interactions with the peptide backbone provides a molecular explanation of how EMIMCl suppresses protein aggregation and simultaneously promotes refolding. By contrast, high concentrations of EMIMCl denature proteins because of a reduced water content and strong favorable interactions with amino acid side chains. This denatured species is not soluble and aggregates because, in contrast to the classical denaturants, guanidine hydrochloride and urea, EMIMCl does not solubilize the peptide backbone.
  PNP and PNP bind by molecular sieving (1, 2, 3, 4).
authors: Division of Hematology, Departments of Internal Medicine, Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA.
authors: Alexander
authors: A
authors: Tischer
authors: Heiko
authors: H
authors: Pultke
authors: Andrea
authors: A
authors: Topf
authors: Matthew
authors: M
authors: Auton
authors: Christian
authors: C
authors: Lange
authors: Hauke
authors: H
authors: Lilie
mesh_terms: D002712:Chlorides / Q000737:chemistry; D007093:Imidazoles / Q000737:chemistry*; D010960:Plasminogen Activators / Q000737:chemistry*; D011489:Protein Denaturation; D017510:Protein Folding; D012995:Solubility; D012997:Solvents / Q000737:chemistry*
chemical_list: D002712:Chlorides; D007093:Imidazoles; D012997:Solvents; D010960:Plasminogen Activators
keywords: CM-rPA; EMIMCl; aggregation; protein solubility; tc-rPA