Complete resonance assignments of the proton NMR spectrum of gonadoliberin (in its native amide and free acid forms) have been obtained using two-dimensional nuclear magnetic resonance spectroscopy under three different environmental conditions, namely, dimethyl sulphoxide solution, aqueous solution and lipid-bound form in model membranes. The proton chemical shifts in the three cases have been compared to derive information about inherent conformational characteristics of the molecule. It has been inferred that the molecule possesses no short-range or long-range order under any of the three solvent conditions. However, there is a nonspecific increase in the linewidths when gonadoliberin is bound to model membranes, indicating a reduced internal motion in the molecule due to lipid-peptide interactions.
nuclear Overhauser enhancement spectroscopy
5-oxoproline or pyroglutamic acid