UV spectroscopy of entire proteins in the gas phase

In-trap photoinduced electron detachment was performed on negatively charged proteins with molecular weights ranging from 8.6 to 77 kDa. The advantages of photodetachment over photodissociation are discussed in the context of action spectroscopy of very large ions. The resulting gas phase photodetachment yield spectra recorded in the UV range (220-310 nm) are presented and are compared with solution absorption spectra. The important question of the influence of the conformation and charge state of a protein on its optical gas phase spectrum is raised. (C) 2010 Elsevier B.V. All rights reserved.