Temperature dependence of gas-phase conformations for ubiquitin ions characterized by proton transfer reactions

► Proton transfer from multiply-protonated ubiquitin ions to 1-butylamine was studied. ► Temperature dependence of absolute reaction rate constants was determined. ► Observed branching fractions were represented with a scheme of sequential process. ► For +7 charge state, conformation of product ion is different from that of parent ion.