title: Improved non-chromatographic purification of a recombinant protein by cationic elastin-like polypeptides.
abstract: This paper reports an improvement in the purification of thioredoxin (Trx) expressed from E. coli by inverse transition cycling (ITC) using cationic elastin-like polypeptides (ELPs). Two ELP libraries having 2% and 5% lysine residues and molecular weights ranging from 4 to 61.1 kDa showed greater salt sensitivity in their inverse transition behavior than purely aliphatic ELPs. Expression yield of Trx-ELP fusions was an unpredictable function of guest residue composition, but reducing the molecular weight of the ELP tag generally increased Trx yield. A cationic 4.3 kDa ELP is the shortest ELP used to purify any protein by ITC to date. A 15.9 kDa ELP with a guest residue composition of K:V:F of 1:7:1 was found to be the optimal cationic tag to purify Trx, as it provided 50% greater Trx yield and only required one-fifth the added NaCl for purification of Trx as compared to previously used aliphatic ELP tags.
authors.affiliation: Department of Biomedical Engineering, Box 90281, Duke University, Durham, North Carolina 27708-0281, USA.
authors.forename: Dong Woo
authors.initials: DW
authors.lastname: Lim
authors.forename: Kimberly
authors.initials: K
authors.lastname: Trabbic-Carlson
authors.forename: J Andrew
authors.initials: JA
authors.lastname: Mackay
authors.forename: Ashutosh
authors.initials: A
authors.lastname: Chilkoti
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D002412:Cations / Q000737:chemistry; D004549:Elastin / Q000096:biosynthesis / Q000737:chemistry* / Q000235:genetics; D004926:Escherichia coli / Q000737:chemistry / Q000235:genetics; D008969:Molecular Sequence Data; D019151:Peptide Library; D010455:Peptides / Q000737:chemistry* / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000302:isolation & purification*; D012965:Sodium Chloride / Q000737:chemistry; D013879:Thioredoxins / Q000096:biosynthesis / Q000737:chemistry / Q000302:isolation & purification*
chemical_list: D002412:Cations; D019151:Peptide Library; D010455:Peptides; D011993:Recombinant Fusion Proteins; D012965:Sodium Chloride; D013879:Thioredoxins; D004549:Elastin