Solution structure of Grb2 reveals extensive flexibility necessary for target recognition.
Grb2 is an adaptor protein composed of a single SH2 domain flanked by two SH3 domains. Grb2 functions as an important evolutionary conserved link between a variety of cell membrane receptors and the Ras/MAP kinase-signaling cascade. Here, we describe the solution structure of Grb2 as revealed by NMR and small angle X-ray scattering measurements. We demonstrate that Grb2 is a flexible protein in which the C-terminal SH3 domain is connected to the SH2 domain via a flexible linker. This is in contrast to the previously described Grb2 crystal structure, which showed a compact structure with intramolecular contact between two SH3 domains. Binding experiments on Grb2 and peptides containing two different proline-rich sequences indicate that Grb2 adapts the relative position and orientation of the two SH3 domains to bind bivalently to the target peptide sequences.
Yuzawa
S
S
Department of Structural Biology, Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo, 060-0812, Japan.
Yokochi
M
M
Hatanaka
H
H
Ogura
K
K
Kataoka
M
M
Miura
K
K
Mandiyan
V
V
Schlessinger
J
J
Inagaki
F
F
D048868:Adaptor Proteins, Signal Transducing; D000595:Amino Acid Sequence; D003198:Computer Simulation; D051380:GRB2 Adaptor Protein; D006801:Humans; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation; D018583:Pliability; D011392:Proline / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D017433:Protein Structure, Secondary; D011506:Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D012984:Software; D012996:Solutions; D013379:Substrate Specificity; D014961:X-Ray Diffraction; D018909:src Homology Domains
D048868:Adaptor Proteins, Signal Transducing; D051380:GRB2 Adaptor Protein; C495948:GRB2 protein, human; D008024:Ligands; D011506:Proteins; D012996:Solutions; D011392:Proline