title: Tunable charge tags for electron-based methods of peptide sequencing: design and applications.
abstract: Charge tags using basic auxiliary functional groups 6-aminoquinolinylcarboxamido, 4-aminopyrimidyl-1-methylcarboxamido, 2-aminobenzoimidazolyl-1-methylcarboxamido, and the fixed-charge 4-(dimethylamino)pyridyl-1-carboxamido moiety are evaluated as to their properties in electron transfer dissociation mass spectra of arginine C-terminated peptides. The neutral tags have proton affinities that are competitive with those of amino acid residues in peptides. Charge reduction by electron transfer from fluoranthene anion-radicals results in peptide backbone dissociations that improve sequence coverage by providing extensive series of N-terminal c-type fragments without impeding the formation of C-terminal z fragments. Comparison of ETD mass spectra of free and tagged peptides allows one to resolve ambiguities in fragment ion assignment through mass shifts of c ions. Simple chemical procedures are reported for N-terminal tagging of Arg-containing tryptic peptides.
authors.affiliation: Department of Chemistry, University of Washington, Bagley Hall, Box 351700, Seattle, WA 98195-1700, USA.
authors.forename: Magdalena
authors.initials: M
authors.lastname: Zimnicka
authors.forename: Christopher L
authors.initials: CL
authors.lastname: Moss
authors.forename: Thomas W
authors.initials: TW
authors.lastname: Chung
authors.forename: Renjie
authors.initials: R
authors.lastname: Hui
authors.forename: František
authors.initials: F
authors.lastname: Tureček
mesh_terms: D000578:Amidines / Q000737:chemistry; D000634:Aminoquinolines / Q000737:chemistry; D010455:Peptides / Q000737:chemistry*; D011522:Protons; D011726:Pyridinium Compounds / Q000737:chemistry; D020539:Sequence Analysis, Protein / Q000379:methods*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D013816:Thermodynamics
chemical_list: D000578:Amidines; D000634:Aminoquinolines; D010455:Peptides; D011522:Protons; D011726:Pyridinium Compounds