High-energy collisions of multiply charged lysozyme ions in gases

An electrospray ion source has been mounted on an accelerator mass spectrometer of the isotope separator type. The multiply charged ions produced by the ion source are accelerated to a kinetic energy of 50z keV, where z is the charge state of the ion. The conformation of disulfide-bond intact and disulfide-bond reduced lysozyme ions with charge states between +7 and +17 has been studied by measurements of single collision destruction cross sections in collisions with He and Xe. For disulfide-bond intact lysozyme ions the cross sections are smaller and less influenced by charge state variation than for disulfide-bond reduced lysozyme. The destruction cross sections are modeled by semielastic collisions between individual molecular atoms and target atoms with an assumption of a charge-state dependent unfolding of the lysozyme structure. (C) 2001 Elsevier Science B.V.