Direct characterization of intact polypeptides by matrix-assisted laser desorption electrospray ionization quadrupole Fourier transform ion cyclotron resonance mass spectrometry.
We report the characterization of a recently introduced hybrid ionization source, matrix-assisted laser desorption electrospray ionization (MALDESI), coupled to a quadrupole Fourier transform ion cyclotron resonance mass spectrometry (QFT-ICR-MS) system. We first demonstrate the ability of MALDESI-QFT-ICR MS to directly analyze and provide high mass measurement accuracy (approximately 1 part-per-million) of a polypeptide using internal calibration. Second, we show the potential of MALDESI-QFT-ICR MS for the top-down characterization of multiply charged polypeptide cations. Finally, we demonstrate sub-femtomole detection limits in MALDESI-QFT-ICR MS using a combination of naturally occurring peptides and their respective stable isotope labeled forms. The results presented herein demonstrate the feasibility of several potential applications for MALDESI-QFT-ICR MS for the direct analysis of intact biological molecules.
Sampson
Jason S
JS
W. M. Keck FT-ICR Mass Spectrometry Laboratory, Department of Chemistry, North Carolina State University, Raleigh, NC 27695, USA.
Hawkridge
Adam M
AM
Muddiman
David C
DC
D017357:Cyclotrons; D008832:Microchemistry / Q000379:methods*; D008970:Molecular Weight; D010455:Peptides / Q000737:chemistry*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods*
D010455:Peptides