Application of higher energy collisional dissociation (HCD) to the fragmentation of new DOTA‐based labels and N‐termini DOTA‐labeled peptides

Abstract

1,4,7,10-Tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) derivatives are applied in quantitative proteomics owing to their ability to react with different functional groups, to harbor lanthanoides and hence their compatibility with molecular and elemental mass spectrometry. The new DOTA derivatives, namely Ln-MeCAT-Click and Ln-DOTA-Dimedone, allow efficient thiol labeling and targeting sulfenation as an important post-translational modification, respectively. Quantitative applications require the investigation of fragmentation behavior of these reagents. Therefore, the fragmentation behavior of Ln-MeCAT-Click and Ln-DOTA-Dimedone was studied using collision-induced dissociation (CID), infrared multiphoton dissociation (IRMPD) and higher-energy collision dissociation (HCD) using different energy levels, and the efficiency of reporter ion production was estimated. The efficiency of characteristic fragment formation was in the order IRMPD > HCD (normal energy level) > CID. On the other hand, the application of HCD at high energy levels (HCD@HE; NCE > 250%) resulted in a significant increase in reporter ion production (33-54%). This new strategy was successfully applied to generate label-specific reporter ions for DOTA amino labeling at the N-termini and in a quantitative fashion for the estimation of amino:thiol ratio in peptides. Copyright © 2017 John Wiley & Sons, Ltd.

Molecules and elements for quantitative bioanalysis: The allure of using electrospray, MALDI, and ICP mass spectrometry side‐by‐side

“…One limitation is the choice of the MS/MS activation method, since the first data showed only useful fragmentation with IRMPD . By systematic analysis of the fragmentation behavior of the DOTA labels first and of labeled peptides with different activation methods and chemically different labels, it became evident that the nature of the labels plays an important role as well . Recently, with HCD in Orbitrap instruments, lanthanoide and, for platinated species, platinum signals were generated from metal‐carrying molecules that allow quantification as well at very low detection levels and no noise limitation (Figure ).…”

“…By systematic analysis of the fragmentation behavior of the DOTA labels first and of labeled peptides with different activation methods and chemically different labels, it became evident that the nature of the labels plays an important role as well . Recently, with HCD in Orbitrap instruments, lanthanoide and, for platinated species, platinum signals were generated from metal‐carrying molecules that allow quantification as well at very low detection levels and no noise limitation (Figure ). This again opens up a new option for quantitation, since metal signals have not been studied from molecular species before in an Orbitrap mass spectrometer.…”