CHEMICAL-SHIFT ASSIGNMENTS AND SECONDARY STRUCTURE OF THE GRB2 SH2 DOMAIN BY HETERONUCLEAR NMR-SPECTROSCOPY

The growth factor receptor-bound protein-2 (Grb2) is an adaptor protei n that mediates signal transduction pathways. Chemical shift assignmen ts were obtained for the SH2 domain of Grb2 by heteronuclear NMR spect roscopy, employing the uniformly C-13-/N-15-enriched protein as well a s the protein containing selectively N-15-enriched amino acids. Using the Chemical Shift Index (CSI) method, the chemical shift indices of f our nuclei, H-1(alpha), C-13(alpha), C-13(beta) and (CO)-C-13, were us ed to derive the secondary structure of the protein. Nuclear Overhause r enhancements (NOEs) were then employed to confirm the secondary stru cture. The CSI results were compared to the secondary structural eleme nts predicted for the Grb2 SH2 domain from a sequence alignment [Lee e t al. (1994) Structure, 2, 423-438]. The core structure of the SH2 dom ain contains an antiparallel beta-sheet and two alpha-helices. In gene ral, the secondary structural elements determined from the CSI method agree well with those predicted from the sequence alignment.