Increased coverage in the transmembrane domain with activated-ion electron capture dissociation for top-down Fourier-transform mass spectrometry of integral membrane proteins

摘要

The c-subunit of ATP synthase (AtpH) is an 8 kD integral membrane protein with two transmembrane domains; we set out to demonstrate it amenable to top-down electrospray-ionization Fourier-transform mass spectrometry ( FT-MS) using both collision activated and electron capture dissociation ( CAD/ECD). Thermal activation concomitant with electron delivery was necessary for efficient ECD ( activated-ion ECD; aiECD), yielding complementary information and greater sequence coverage in the transmembrane domains in comparison with CAD.