Top-down mass spectrometry of integral membrane proteins.
Top-down mass spectrometry focuses on intact proteins, thereby avoiding loss of information accompanying 'shotgun' protocols that reduce the proteome to a collection of peptides. A suite of liquid-chromatography technologies has been developed for purification of intact integral membrane proteins in aqueous/organic solvent mixtures compatible with biological 'soft-ionization' mass spectrometry, preserving covalent structure into the gas phase. Multiply charged protein ions are fragmented in the gas phase, using either collision-activated or electron-capture dissociation, thus yielding complex spectra of sequence-dependent product ions that collectively define the original native covalent state of an intact protein. Top down offers a more detail-orientated approach to post-transcriptional and post-translational diversity allowing an enhanced insight beyond genomic translation, which has now extended into the bilayer proteome.
Whitelegge
Julian
J
University of California, Pasarow Mass Spectrometry Laboratory, Jane and Terry Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, Los Angeles, CA 90024, USA. jpw@chem.ucla.edu
Halgand
Frederic
F
Souda
Puneet
P
Zabrouskov
Vlad
V
D000818:Animals; D001436:Bacteriorhodopsins / Q000737:chemistry; D006801:Humans; D013058:Mass Spectrometry / Q000379:methods*; D008565:Membrane Proteins / Q000737:chemistry*; D040901:Proteomics
D008565:Membrane Proteins; D001436:Bacteriorhodopsins