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Use of 1,5‐diaminonaphthalene to combine matrix‐assisted laser desorption/ionization in‐source decay fragmentation with hydrogen/deuterium exchange
Author(s) -
Lemaire Pascale,
Debois Delphine,
Smargiasso Nicolas,
Quinton Loïc,
Gabelica Valérie,
De Pauw Edwin A.
Publication year - 2013
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.6627
Subject(s) - chemistry , hydrogen–deuterium exchange , fragmentation (computing) , deuterium , matrix assisted laser desorption/ionization , mass spectrometry , desorption , ionization , regioselectivity , maldi imaging , dissociation (chemistry) , matrix isolation , matrix (chemical analysis) , hydrogen , analytical chemistry (journal) , ion , chromatography , molecule , atomic physics , organic chemistry , catalysis , physics , adsorption , computer science , operating system
RATIONALE In‐Source Decay (ISD) in Matrix‐Assisted Laser Desorption/Ionization (MALDI) mass spectrometry is a fast and easy top‐down activation method. Our objective is to find a suitable matrix to locate the deuterons following in‐solution hydrogen/deuterium exchange (HDX). This matrix must circumvent the commonly encountered undesired back‐exchange reactions, in order to preserve the regioselective deuteration pattern. METHODS The 1,5‐diaminonaphthalene (1,5‐DAN) matrix is known to be suitable for MALDI‐ISD fragmentation. MALDI Mass Spectrometry Imaging (MSI) was employed to compare 1,5‐DAN and other commonly used MALDI matrices with respect to the extent of back‐exchange and the uniformity of the H/D exchange profiles within the MALDI spots. We tested the back‐exchange on the highly sensitive amyloid‐beta peptide (1‐40), and proved the regioselectivity on ubiquitin and β‐endorphin. RESULTS MALDI‐MSI results show that 1,5‐DAN leads to the least back‐exchange over all the spot. MALDI‐ISD fragmentation combined with H/D exchange using 1,5‐DAN matrix was validated by localizing deuterons in native ubiquitin. Results agree with previous data obtained by Nuclear Magnetic Resonance (NMR) and Electron Transfer Dissociation (ETD). Moreover, 1,5‐DAN matrix was used to study the H/D exchange profile of the methanol‐induced helical structure of β‐endorphin, and the relative protection can be explained by the polarity of residues involved in hydrogen bond formation. CONCLUSIONS We found that controlling crystallization is the most important parameter when combining H/D exchange with MALDI. The 1,5‐DAN matrix is characterized by a fast crystallization kinetics, and therefore gives robust and reliable H/D exchange profiles using MALDI‐ISD. Copyright © 2013 John Wiley & Sons, Ltd.