Contribution of the residue Glu9, Glu46, and Phe49 to the biological activity of insulin-like growth factor-1.
Three recombinant single-chain insulin mutants, [B10Glu]Ins/IGF-1(C), [A5Glu]PIP, and [A8Tyr]PIP were prepared by means of protein engineering. In the three mutants, the residue at position 10 of insulin B chain and positions 5 and 8 of insulin A chain were substituted by the corresponding residue Glu9, Glu46, and an aromatic residue at 49 of IGF-1, respectively. The growth-promoting activity of [B18Glu]Ins/IGF-1(C) is 58-fold higher than insulin and of [A5Glu]PIP, and [A8Tyr]PIP is 2.5- and 4.7-fold higher than PIP, respectively, measured using a mouse mammary tumor cell line GR2H6 in vitro. The results show that the residues Glu9, Glu46, and Phe49, especially the Glu9, play an important role in the growth-promoting function of IGF-1. Based on the results, we suggest that the insulin could be used as a scaffold to investigate the contributions of residues of IGF-1 to its biological function.
Chen
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State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, People's Republic of China.
Feng
Y M
YM
D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000818:Animals; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D003001:Cloning, Molecular; D003470:Culture Media; D004926:Escherichia coli / Q000235:genetics; D005260:Female; D018698:Glutamic Acid; D006801:Humans; D007328:Insulin / Q000737:chemistry / Q000235:genetics* / Q000494:pharmacology; D007334:Insulin-Like Growth Factor I / Q000737:chemistry* / Q000494:pharmacology*; D015674:Mammary Neoplasms, Animal / Q000473:pathology; D051379:Mice; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D010649:Phenylalanine; D011994:Recombinant Proteins / Q000737:chemistry; D014407:Tumor Cells, Cultured
D003470:Culture Media; D007328:Insulin; D011994:Recombinant Proteins; D018698:Glutamic Acid; D010649:Phenylalanine; D007334:Insulin-Like Growth Factor I