title: Recognition of an antiparallel beta-sheet structure of human epidermal growth factor by its receptor. Site-directed mutagenesis studies of Ala-30 and Asn-32.
abstract: The Ala-30 and Asn-32 residues involved in the major antiparallel beta-sheet structure of human epidermal growth factor (hEGF) were substituted with various amino acid residues, and the receptor-binding affinities of the nine variant hEGFs were determined by the use of human KB cells. The Ala-30----Arg, Ala-30----His and Ala-30----Phe substitutions drastically reduced the binding affinity, suggesting that the side chain in position 30 of Ala-30 of hEGF is required to be small for the receptor binding. The Asn-32----Asp substitution significantly reduced the binding affinity, while the Asn-32----His variant could bind to the receptor as well as to the wild-type hEGF. Therefore, it seems to be important for receptor binding that the side chain in position 32 does not have a negative charge but does have an NH group. Thus, we propose that, in the ligand-receptor complex, the receptor recognizes, on one side of the antiparallel beta-sheet structure of hEGF, a wider contact area than previously suggested.
authors.affiliation: Department of Biophysics and Biochemistry, Faculty of Science, University of Tokyo, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Koide
authors.forename: Y
authors.initials: Y
authors.lastname: Muto
authors.forename: H
authors.initials: H
authors.lastname: Kasai
authors.forename: K
authors.initials: K
authors.lastname: Hoshi
authors.forename: H
authors.initials: H
authors.lastname: Takusari
authors.forename: K
authors.initials: K
authors.lastname: Kohri
authors.forename: S
authors.initials: S
authors.lastname: Takahashi
authors.forename: T
authors.initials: T
authors.lastname: Sasaki
authors.forename: K
authors.initials: K
authors.lastname: Tsukumo
authors.forename: T
authors.initials: T
authors.lastname: Miyake
mesh_terms: D000409:Alanine / Q000378:metabolism; D001216:Asparagine / Q000378:metabolism; D001667:Binding, Competitive; D004815:Epidermal Growth Factor / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D066246:ErbB Receptors / Q000378:metabolism*; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D016297:Mutagenesis, Site-Directed; D011487:Protein Conformation
chemical_list: D004815:Epidermal Growth Factor; D001216:Asparagine; D066246:ErbB Receptors; D000409:Alanine