title: Interaction of a 43-kDa receptor-like protein with a 4-kDa hormone-like peptide in soybean.
abstract: A 43-kDa soybean protein is a receptor-like protein kinase that is capable of interaction with a 4-kDa hormone-like peptide (leginsulin). The 43-kDa protein consists of alpha and beta subunits; the beta subunit has protein kinase activity that is stimulated by the binding of the 4-kDa peptide. The protein kinase activity is believed to be an early step in a signal transduction cascade, triggered by the peptide. Animal insulin also interacts with the 43-kDa protein and stimulates the protein kinase activity, suggesting that the 4-kDa peptide and insulin bind to the 43-kDa protein with similar mechanisms. To determine the mechanism of interaction between the 4-kDa peptide and 43-kDa protein, we investigated the binding region of the 4-kDa peptide on the 43-kDa protein using surface plasmon resonance (SPR) spectroscopy. We found that the N- (amino acids 1-43) and C-terminal (amino acids 228-251) regions of the alpha subunit of the 43-kDa protein are involved in the binding. The interactions of both insulin and the 4-kDa peptide with the 43-kDa protein were compared using SPR spectroscopy, revealing that insulin binds to the C-terminal regions of the alpha subunit of the 43-kDa protein. These results suggest that the C-terminal region is especially important for the biological function. The N-terminal region is thought to play an important role in stabilizing the complex of the 43-kDa protein and the 4-kDa peptide.
authors.affiliation: Graduate School of Integrated Science, Kihara Institute for Biological Research, Yokohama City University, Maioka-cho 641-12, Totsuka, Yokohama 244-0813, Japan.
authors.forename: Kazuki
authors.initials: K
authors.lastname: Hanada
authors.forename: Hisashi
authors.initials: H
authors.lastname: Hirano
mesh_terms: D000409:Alanine / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence; D001665:Binding Sites; D050260:Carbohydrate Metabolism; D006728:Hormones / Q000737:chemistry*; D007328:Insulin / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009154:Mutation / Q000235:genetics; D010446:Peptide Fragments / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D021122:Protein Subunits / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D030262:Soybean Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D013025:Glycine max / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D006728:Hormones; D007328:Insulin; D010446:Peptide Fragments; D021122:Protein Subunits; D030262:Soybean Proteins; D000409:Alanine