Peptide and protein characterization by high‐rate electron capture dissociation Fourier transform ion cyclotron resonance mass spectrometry

Abstract

The analytical utility of the electron capture dissociation (ECD) technique, developed by McLafferty and co-workers, has substantially improved peptide and protein characterization using Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS). The limitations of the first ECD implementations on commercial instruments were eliminated by the employment of low-energy electron-injection systems based on indirectly heated dispenser cathodes. In particular, the ECD rate and reliability were greatly increased, enabling the combination of ECD/FTICR-MS with on-line liquid separation techniques. Further technique development allowed the combination of two rapid fragmentation techniques, high-rate ECD and infrared multiphoton dissociation (IRMPD), in a single experimental configuration. Simultaneous and consecutive irradiations of trapped ions with electrons and photons extended the possibilities for ion activation/dissociation and led to improved peptide and protein characterization. The application of high-rate ECD/FTICR-MS has demonstrated its power and unique capabilities in top-down sequencing of peptides and proteins, including characterization of post-translational modifications, improved sequencing of peptides with multiple disulfide bridges and secondary fragmentation (w-ion formation). Analysis of peptide mixtures has been accomplished using high-rate ECD in bottom-up mass spectrometry based on mixture separation by liquid chromatography and capillary electrophoresis. This paper summarizes the current impact of high-rate ECD/FTICR-MS for top-down and bottom-up mass spectrometry of peptides and proteins.

Use of 18O labels to monitor deamidation during protein and peptide sample processing

“…ECD experiments used an indirectly heated dispenser cathode placed about 3 cm from the cell [53][54][55]. The control samples were electrosprayed at approximately 10 Ϫ5 M concentration in 49.5:49.5:1 of methanol:water:formic acid spray solution, whereas the 18 O-labeled samples were electrosprayed at the same concentration, but in 24.5:74.5:1 of methanol:water:formic acid spray solution.…”

Comparison of infrared multiphoton dissociation and collision-induced dissociation of supercharged peptides in ion traps

“…Recently, electron capture dissociation (ECD) [2] in Fourier transform ion cyclotron resonance (FT-ICR) instruments, a method that involves the reaction of multiply charged cations with low-energy electrons, and electron-transfer dissociation (ETD) [3] in ion trap instruments, a technique that exploits the reaction of multiply charged cations with radical anions, have been developed to combat this neutral loss problem by affording complementary c-and z-type backbone cleavages that leave labile modifications intact. These methods have been particularly promising for characterization of PTMs [4 -8]; however, both techniques suffer from low fragmentation efficiencies, especially for lower charge states [9, 10], compared with CID.Infrared multiphoton dissociation (IRMPD) is another tandem MS (MS/MS) method that has been successfully implemented in FT-ICR, time-of-flight, and quadrupole ion trap instrument systems [6,[11][12][13][14][15][16][17][18][19][20][21][22][23][24]. Much of the appeal of IRMPD in quadrupole ion traps is related to the broader m/z trapping range possible than that for conventional CID.…”

“…Infrared multiphoton dissociation (IRMPD) is another tandem MS (MS/MS) method that has been successfully implemented in FT-ICR, time-of-flight, and quadrupole ion trap instrument systems [6,[11][12][13][14][15][16][17][18][19][20][21][22][23][24]. Much of the appeal of IRMPD in quadrupole ion traps is related to the broader m/z trapping range possible than that for conventional CID.…”

Electron capture dissociation implementation progress in fourier transform ion cyclotron resonance mass spectrometry

“…lectron capture dissociation (ECD) in Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) is one of the most prominent methods for complete peptide and protein structural characterization [1][2][3][4][5]. The analytical power of ECD in FT-ICR MS encouraged researchers to develop alternative methods for lower resolution mass spectrometers.…”