500 MHz NMR characterization of synthetic bombesin and related peptides in DMSO‐d6 by two‐dimensional techniques

The proton NMR characterization of bombesin has been carried out at 500 MHz in DMSO‐d6 using two‐dimensional homo‐ and 1H‐13C hetero‐correlated techniques. All resonances in the NMR spectra have been assigned and several coupling constants have been measured. The backbone J αCH‐NH coupling constants have constant values that vary between 7.8 and 8.2 Hz and indicate an unfolded structure in DMSO‐d6. Discrepancies with data recently obtained at 300 MHz [(1987) Eur. J. Biochem. 168, 193–199] are discussed.