High Yield Expression and Purification of Human Endothelin-1

• Published in: Protein expression and purification Vol. 5; no. 6; pp. 559 - 568
• Main Authors: Fassina, G., Merli, S., Germani, S., Ciliberto, G., Cassani, G.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.12.1994
• Subjects: Amino Acid Sequence; ATP-Binding Cassette Transporters; Base Sequence; Carrier Proteins; Chromatography, Affinity; Chromatography, High Pressure Liquid; Chymotrypsin; Cloning, Molecular; Endopeptidases; Endothelin-1; Endothelins - biosynthesis; Endothelins - isolation & purification; Escherichia coli - metabolism; Escherichia coli Proteins; Humans; Maltose-Binding Proteins; Molecular Sequence Data; Monosaccharide Transport Proteins; Polymerase Chain Reaction; Protein Precursors - biosynthesis; Protein Precursors - isolation & purification; Recombinant Fusion Proteins - biosynthesis
• ISSN: 1046-5928; 1096-0279
• DOI: 10.1006/prep.1994.1077

A DNA construct encoding human big endothelin (Big ET) preceded by the factor Xa protease recognition site (Ile-Glu-Gly-Arg), fused in frame to the maltose binding protein sequence, has been introduced in DH5-α cells. The fusion product (MBP-Big ET) was expressed at a concentration close to 100 μg/ml of culture broth and constituted approximately 50% of the total protein content. Crude cell extracts containing the fusion product have been directly treated with trypsin under mild denaturing conditions in order to release big endothelin (1-37) from the adduct. Cleavage yield of the MBP-Big ET adduct was close to 70%. Big ET(1-37) was separated from unrelated peptides derived from the tryptic digest of the bacterial extract by affinity chromatography. The affinity column was prepared by immobilizing a protease resistant peptide ligand able to recognize Big ET with sufficient affinity, selectivity, and specificity. From the affinity step (recovery, 90%), recombinant Big ET(1-37) was obtained with a purity close to 80%. The affinity-purified recombinant product was then digested with α-chymotrypsin in order to release endothelin (1-21), which was then purified by RP-HPLC. With this two-step purification protocol, 3 μg of endothelin was recovered from 1 ml of bacterial broth, with a purity close to 95%.