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See detailUse of 1,5-diaminonaphthalene to combine matrix-assisted laser desorption/ionization in-source decay fragmentation with hydrogen/deuterium exchange
Lemaire, Pascale; Debois, Delphine ULg; Smargiasso, Nicolas ULg et al

in Rapid Communications in Mass Spectrometry [=RCM] (2013), 27(16), 1837-1846

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 ... [more ▼]

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. 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 b-endorphin. 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 b-endorphin, and the relative protection can be explained by the polarity of residues involved in hydrogen bond formation. 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. [less ▲]

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See detail2D DIGE, label free quantification, principal component and mass spectrometry analysis for biomarkers discovery in MCF-7/BOS cells exposed to 17β-estradiol and endocrine disruptors.
Collodoro, Mike ULg; Lemaire, Pascale; Eppe, Gauthier ULg et al

in Organohalogen Compounds (2011)

Endocrine system disruption has become a subject of great interest over the last few decades, since it has become evident that natural and also synthetic substances can mimic or reduce the activity of ... [more ▼]

Endocrine system disruption has become a subject of great interest over the last few decades, since it has become evident that natural and also synthetic substances can mimic or reduce the activity of endogenous hormones. Compounds with estrogenic activity are an important family of potential endocrine disruptors that have to be monitored either in the food chain or in the environment. Estrogens are known to induce or promote hormonal dependent cancers, to reduce sperm counts and fertility in men and generate the feminization of exposed wildlife populations. The rapid screening of unwanted chemicals in the food chain is beset by difficulties. The number of toxic compounds is very large and no universal method can cope with their diversity. In this work, emergent differential proteomic techniques are used to discover a set of biomarkers for the development of a multiple estrogen contaminants screening test. [less ▲]

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