title: New approach for pseudo-MS(3) analysis of peptides and proteins via MALDI in-source decay using radical recombination with 1,5-diaminonaphthalene.
abstract: Matrix-assisted laser desorption ionization in-source decay (MALDI-ISD) is a useful method for top-down sequencing of proteins and preferentially produces the c'/z(•) fragment pair. Subsequently, radical z(•) fragments undergo a variety of radical reactions. This work is focused on the chemical properties of the 1,5-diaminonaphthalene (1,5-DAN) adducts on z fragment ions (zn*), which are abundant in MALDI-ISD spectra. Postsource decay (PSD) of the zn* fragments resulted in specific peptide bond cleavage adjacent to the binding site of 1,5-DAN, leading to the preferential formation of y'n-1 fragments. The dominant loss of an amino acid with 1,5-DAN from zn* can be used in pseudo-MS(3) mode to identify the C-terminal side fragments from a complex MALDI-ISD spectrum or to determine missed cleavage residues using MALDI-ISD. Although the N-Cα bond at the N-terminal side of Pro is not cleaved by MALDI-ISD, pseudo-MS(3) via zn* can confirm the presence of a Pro residue.
authors: Chemistry Department, Mass Spectrometry Laboratory and GIGA-R, University of Liege , 4000 Liege, Belgium.
authors: Daiki
authors: D
authors: Asakawa
authors: Nicolas
authors: N
authors: Smargiasso
authors: Edwin
authors: E
authors: De Pauw
mesh_terms: D015081:2-Naphthylamine / Q000031:analogs & derivatives* / Q000737:chemistry; D010455:Peptides / Q000032:analysis*; D011506:Proteins / Q000032:analysis*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
chemical_list: D010455:Peptides; D011506:Proteins; C510889:1,5-diaminonaphthalene; D015081:2-Naphthylamine