Skip to main content
. Author manuscript; available in PMC: 2017 Feb 1.
Published in final edited form as: Anal Chem. 2016 May 13;88(11):5879–5884. doi: 10.1021/acs.analchem.6b00691

Figure 2.

Figure 2

Charge-corrected Ω (Ω′) of a set of soluble (round data points) and membrane proteins (square data points) as a function of corrected drift time (td′). (a–c) At a fixed wave velocity of 350 m/s, membrane proteins and calibrant ions separate into distinct Ω′ regimes. This separation is not affected by wave height. The data from panel (a) are plotted as the ‘doubly-corrected’ drift time vs. Ω in Figure S2 to illustrate in this alternative representation the deviation of membrane proteins from soluble proteins. (d) The plot of Ω′ of native-like and unfolded membrane protein AmtB as a function of td′ shows that the species cannot be matched by a single calibration curve. (e) Charge reduction bridges the difference in mobility between ConA and the membrane protein AqpZ. (f) PKin is a suitable calibrant protein for approximating the Ω of AmtB by TWIMS. Selected charge states for each protein are listed in Table S6. WH: wave height; WV: wave velocity.