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Multiple Ionization of Free Ubiquitin Molecular Ions in Extreme Ultraviolet Free‐Electron Laser Pulses
Author(s) -
Schlathölter Thomas,
Reitsma Geert,
Egorov Dmitrii,
GonzalezMagaña Olmo,
Bari Sadia,
Boschman Leon,
Bodewits Erwin,
Schnorr Kirsten,
Schmid Georg,
Schröter Claus Dieter,
Moshammer Robert,
Hoekstra Ronnie
Publication year - 2016
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201605335
Subject(s) - fragmentation (computing) , ionization , ion , chemistry , atomic physics , extreme ultraviolet , electron ionization , excitation , femtosecond , electron , photodissociation , photochemistry , laser , physics , optics , organic chemistry , quantum mechanics , computer science , operating system
The fragmentation of free tenfold protonated ubiquitin in intense 70 femtosecond pulses of 90 eV photons from the FLASH facility was investigated. Mass spectrometric investigation of the fragment cations produced after removal of many electrons revealed fragmentation predominantly into immonium ions and related ions, with yields increasing linearly with intensity. Ionization clearly triggers a localized molecular response that occurs before the excitation energy equilibrates. Consistent with this interpretation, the effect is almost unaffected by the charge state, as fragmentation of sixfold deprotonated ubiquitin leads to a very similar fragmentation pattern. Ubiquitin responds to EUV multiphoton ionization as an ensemble of small peptides.