Structures of micelle-bound selected insect neuropeptides and analogues: implications for receptor selection

Neuropeptides control essential physiological processes in insects such as water balance and muscle activity. Due to their metabolic instability and adverse physiochemical properties, insect neuropeptides are unsuited for a direct application in plant protection. As a first approximation towards the biologically active conformation, the structures of selected neuropeptides from economically important pest insects were determined by NMR spectroscopy and fluorescence measurements in a membrane-mimicking environment. A receptor binding model is suggested for the helicokinins and discussed in connection with biological activities and membrane-bound conformations of linear and cyclic analogues.