As shown in Figure , the SID monomer product's average charge shows limited variation with increasing isCA, as opposed to the increasing charge states with increasing isCA observed for SA, AV, and CRP, and previously reported by our lab. Figure compares SID product intensities of 15+ TRAP at two different cone voltages, and the 21+ charge state at low cone voltage. Based on the above mentioned papers, it was reasonable to expect that the 21+ charge state (purple bars) would feature non-native-like SID. This is clearly reflected in Figure , where the SID oligomeric product distribution is shifted towards lower oligomeric states, whereas the 15+ charge state at low cone voltage (dark blue bars) appears to have more balance across the oligomeric states, reflecting native-like partitioning when two interfaces are cleaved in an 11mer protein complex. The 15+ charge state at the highest cone voltage (light blue bars) is shifted to favor lower oligomeric states, similar to the 21+ charge state. This clearly shows that a high amount of isCA caused 15+ TRAP to adopt a collapsed quaternary structure, resulting in non-native-like SID.