Oxazolone versus macrocycle structures for Leu-enkephalin b2-b4: insights from infrared multiple-photon dissociation spectroscopy and gas-phase hydrogen/deuterium exchange.

Oxazolone versus macrocycle structures for Leu-enkephalin b2-b4: insights from infrared multiple-photon dissociation spectroscopy and gas-phase hydrogen/deuterium exchange.