High-energy collisions of multiply charged lysozyme ions in gases

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