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The effects of N ‐ethyl‐ N ′‐methyl imidazolium chloride on the solubility, stability and aggregation of tc‐r PA
Author(s) -
Tischer Alexander,
Pultke Heiko,
Topf Andrea,
Auton Matthew,
Lange Christian,
Lilie Hauke
Publication year - 2014
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/febs.12736
Subject(s) - chemistry , guanidine , solubility , side chain , peptide , hydrochloride , guanidinium chloride , urea , amino acid , chloride , aqueous solution , organic chemistry , polymer , biochemistry , enzyme
The ionic liquid N ‐ethyl‐ N ′‐methyl imidazolium chloride ( EMIMC l) has been described as being very efficient in promoting refolding of the recombinant plasminogen activator r PA . Our study reveals that molar concentrations of EMIMC l 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 EMIMC l suppresses protein aggregation and simultaneously promotes refolding. By contrast, high concentrations of EMIMC l 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, EMIMC l does not solubilize the peptide backbone. Structured digital abstractPNP and PNP bind by molecular sieving ( 1 , 2 , 3 , 4 )