Native electron capture dissociation for the structural characterization of noncovalent interactions in native cytochrome c

Selectively cleaved: Under appropriate experimental conditions, electrospray ionization mass spectrometry produces fragment ions that directly indicate non-covalent protein-heme interaction sites in native Cytochrome c (see picture). The proposed mechanism involves asymmetric charge partitioning in gaseous protein dimer ions, which causes electron transfer and subsequent backbone-cleavage.