title: Mutants of human insulin-like growth factor II: expression and characterization of analogs with a substitution of TYR27 and/or a deletion of residues 62-67.
abstract: Five structural analogs of human insulin-like growth factor II (IGF II), [Leu27]IGF II, [Glu27]IGF II, des(62-67)IGF II, des(62-67)[Leu27]IGF II and des(62-67)[Glu27]IGF II were constructed by site-directed mutagenesis and expressed as protein A fusion proteins in E. coli BL21 pLysS cells, cleaved with CNBr and purified by affinity chromatography and HPLC. These mutants were tested for their binding affinities to type 1 and type 2 IGF receptors, to IGF binding protein-3 (IGFBP-3) and for their stimulation of thymidine incorporation into DNA. [Leu27]IGF II exhibits an affinity to the type 2 IGF receptor close to that of wild-type IGF II, but has lost completely the affinity to the type 1 IGF receptor. The results further suggest that the D domain, which is close to Tyr27, forms part of the binding region for the type 1 IGF receptor.
authors.affiliation: Department of Biochemistry, University of Zürich, Switzerland.
authors.forename: B V
authors.initials: BV
authors.lastname: Roth
authors.forename: D M
authors.initials: DM
authors.lastname: Bürgisser
authors.forename: C
authors.initials: C
authors.lastname: Lüthi
authors.forename: R E
authors.initials: RE
authors.lastname: Humbel
mesh_terms: D001483:Base Sequence; D001665:Binding Sites; D002352:Carrier Proteins / Q000378:metabolism; D002846:Chromatography, Affinity; D002851:Chromatography, High Pressure Liquid; D003488:Cyanogen Bromide; D004247:DNA / Q000096:biosynthesis; D004926:Escherichia coli / Q000235:genetics; D015870:Gene Expression; D006801:Humans; D018969:Insulin-Like Growth Factor Binding Proteins; D007335:Insulin-Like Growth Factor II / Q000031:analogs & derivatives / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D011956:Receptors, Cell Surface / Q000378:metabolism; D017451:Receptors, Somatomedin; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D013205:Staphylococcal Protein A
chemical_list: D002352:Carrier Proteins; D018969:Insulin-Like Growth Factor Binding Proteins; D011956:Receptors, Cell Surface; D017451:Receptors, Somatomedin; D011993:Recombinant Fusion Proteins; D013205:Staphylococcal Protein A; D007335:Insulin-Like Growth Factor II; D004247:DNA; D003488:Cyanogen Bromide