title: Glucagon-induced self-association of recombinant proteins in Escherichia coli and affinity purification using a fragment of glucagon receptor.
abstract: The specific molecular interactions of alpha-helical peptide, human glucagon (i.e., intermolecular self-association and specific receptor-binding affinity) provided a rationale for using the glucagon as the fusion expression partner to achieve high productivity of foreign proteins both in vivo (in bacterial fusion-expression system) and in vitro (in affinity column chromatography). The fusion of glucagon peptide(s) effectively promoted homogeneous aggregate formation of recombinant proteins while avoiding intermolecular crosslinking by disulfide bridges. High sensitivity of the self-aggregation to sequence effects resulted from two distinct nonpolar domains of glucagon, determining specificity of molecular interaction and aggregate size of recombinant proteins. An N-terminal domain of glucagon molecule (Phe6-Tyr10-Tyr13) could be a certain hydrophobic moiety involved in intermolecular self-association (probably, via helix-helix docking), while a C-terminal domain (Phe22-Trp25-Leu26) seems to critically affect the oligomer size in the off-pathway aggregation of synthesized fusion proteins. An N-terminal extracellular domain of human glucagon receptor was recombinantly expressed in Escherichia coli, immobilized to a chromatography column, and efficiently renatured to a conformation that attains high specificity in interaction with N-terminus glucagon molecules of recombinant fusion proteins. Through column chromatography employing the receptor fragment as affinity ligand, the recombinant proteins were efficiently purified from total intracellular proteins, and the long-term ligand stability was evidently proven through multiple cyclic-purification experiments. Major scaffolds for using protein ligands are large-scale production in a low-cost expression system and long-term stable operation with selective-binding affinity. From this point of view, the extracellular fragment of human glucagon receptor used in this study seems to be a new potent ligand for fusion protein-based affinity chromatography.
authors.affiliation: Microbial and BioProcess Engineering Laboratory, Korea Research Institute of Bioscience and Biotechnology (KRIBB), P.O. Box 115, Yusong, Taejon 305-600, South Korea.
authors.forename: D Y
authors.initials: DY
authors.lastname: Kim
authors.forename: J
authors.initials: J
authors.lastname: Lee
authors.forename: V
authors.initials: V
authors.lastname: Saraswat
authors.forename: Y H
authors.initials: YH
authors.lastname: Park
mesh_terms: D000595:Amino Acid Sequence; D023181:Antimicrobial Cationic Peptides; D002846:Chromatography, Affinity; D004926:Escherichia coli / Q000378:metabolism*; D005934:Glucagon / Q000737:chemistry / Q000235:genetics*; D006801:Humans; D015151:Immunoblotting; D007376:Interleukin-2 / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D008024:Ligands; D054806:Magainins; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism*; D010455:Peptides / Q000302:isolation & purification; D011485:Protein Binding; D018027:Receptors, Glucagon / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D029867:Xenopus Proteins
chemical_list: D023181:Antimicrobial Cationic Peptides; D007376:Interleukin-2; D008024:Ligands; D054806:Magainins; D010446:Peptide Fragments; D010455:Peptides; D018027:Receptors, Glucagon; D011993:Recombinant Fusion Proteins; D029867:Xenopus Proteins; C053301:magainin 2 peptide, Xenopus; D005934:Glucagon