Conformational characterization of a single-site mutant of murine epidermal growth factor (EGF) by 1H NMR provides evidence that leucine-47 is involved in the interactions with the EGF receptor.
Epidermal growth factor (EGF) is a small protein containing 53 amino acids and three disulfide bonds. There is significant current interest in structure-function relationships in EGF and EGF-like proteins, including the homologous type-alpha transforming growth factors. The Leu-47 residue of murine EGF (mEGF) is one of several that are strongly conserved among the EGF-like growth factors, suggesting that it may contribute to the active site of mEGF. In several different binding assays, the activity of the mutant analog in which Leu-47 is replaced by Ser [( Ser47]mEGF) ranges from 8 to 18 times weaker than that of wild-type mEGF. The NMR data summarized in this paper demonstrate that the significant differences in the binding activities of wild-type and [Ser47]mEGF cannot be attributed to structural changes remote from the three-dimensional site of mutation. The only minor conformational changes that are indicated by these data involve side chains of residues proximal to Leu-47 in the three-dimensional structure. Therefore, Leu-47 and/or residues spatially adjacent to Leu-47 constitute part of the active site of mEGF.
Moy
F J
FJ
Baker Laboratory of Chemistry, Cornell University, Ithaca, NY 14853-1301.
Scheraga
H A
HA
Liu
J F
JF
Wu
R
R
Montelione
G T
GT
D000818:Animals; D001665:Binding Sites; D004815:Epidermal Growth Factor / Q000235:genetics / Q000378:metabolism*; D066246:ErbB Receptors / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics; D007930:Leucine; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D051379:Mice; D008958:Models, Molecular; D009154:Mutation; D011485:Protein Binding; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000378:metabolism
D011994:Recombinant Proteins; D004815:Epidermal Growth Factor; D066246:ErbB Receptors; D007930:Leucine