Developing ICP-MS/MS for the detection and determination of synthetic DNA-protein crosslink models via phosphorus and sulfur detection

Abstract

Various endogenous and exogenous agents drive the un-directed formation of covalent bonds between proteins and DNA. These complex molecules are of great biological relevance, as can derive in mutations, but are difficult to study because of their heterogeneous chemical properties. New analytical approaches with sufficient detection capabilities to detect and quantify these compounds can help to standardize study models based on synthesized standards. The use of atomic spectrometry can provide quantitative information on the DNA-protein cross-link reaction yield along with basic stoichiometry of the products, based on internal elemental tags, sulfur from Cys and Met amino acids, and phosphorus from the DNA. A new instrumental approach to remove isobaric and poly-atomic interferences from 31P+ and 32S+ was developed recently, with state-of-the-art for interference removal that captures 31P+ in Q1; it reacts with O2 in an octopole collision-reaction cell generating 47PO+, therefore allowing detection in Q3 without 31NOH+/48Ca/47Ti interferences. Similarly, 32S+ is reacted to 48SO+, eliminating the polyatomic interferences at m/z=32. In conjunction with the high resolving power of high-performance liquid chromatography (HPLC), this newer technology was applied by to the product purification of a DNA-protein cross link model and some preliminary structural studies.

Quantitative determination of the sulfur-containing antioxidant ergothioneine by HPLC/ICP-QQQ-MS

“…Using the calibration method (DIN 32645), the limits of detection and quantication for ergothioneine obtained with our HPLC/ICP-QQQ-MS method were 0.23 mg S per L and 0.80 mg S per L for m/z 32 / 48. The LOD was comparable to or slightly lower than those obtained for the determination of ergothioneine by LC/molecular MSMS 9,11 or other sulfur containing species by LC-ICP-QQQ-MS [23][24][25][26] and about 1 to 2 orders of magnitude lower compared to LC/UV methods 14,17,19 for the determination of ergothioneine. However, LOD and LOQ values obtained with aqueous ergothioneine standards, as is commonly reported, do not incorporate the inuence of matrix components, which were expected to be signicant in case of the complex matrix of the cell samples.…”

“…Thus in comparison with single quadrupole/reaction cell systems, the triple quadrupole system provides great selectivity and lower background counts, which translates into better detection limits for sulfur. 23 ICP-QQQ-MS has been so far mainly applied to the determination of sulfur in the eld of protein quantication, [23][24][25][26][27] with samples including solutions of sulfur-containing compounds, 23,25 DNAprotein cross-linking reaction products, 24 human plasma 25,26 and snake venom. 27 We present here a HPLC/ICP-QQQ-MS method for the quantitative determination of the health-relevant sulfur compound ergothioneine and its application to cell culture media and cell pellets.…”

ICP-MS/MS as a tool to study abiotic methylation of inorganic mercury reacting with VOCs

“…The productivities of the gaseous CH 3 Hg + ions by CH 3 I in the dark reactor in our work are close to the productivities of the aqueous CH 3 Hg + ions by UV irradiation reported by Yin et al 16 In addition, our work also demonstrates that this methylation reaction can occur even at extremely low gas pressures, for the ORS 3 in the ICP-MS/MS is a near-vacuum environment. 27,[30][31][32][33] In this study, we use an ICP-MS/MS instrument as the tool to study inorganic mercury methylation, which expands the application range of ICP-MS/MS for elements determination. Fig.…”

Application of Molecular Mass Spectrometry for The Structural Characterization of a DNA-Protein Cross-Links

“…adduct from the reaction of 2'-deoxyguanosine and alpha-N-acetyl-lysine-methyl ester was carried as previously reported [27]. A high performance liquid chromatography system (HPLC) consisted on an Agilent 1100 series (Agilent Technologies, Santa Clara, CA, USA), equipped with a binary HPLC pump, an autosampler, a vacuum degasser system, a temperature column compartment, and a diode array detector.…”

“…More recently, peptide sequencing and mass spectrometry (MS) as analytical techniques are playing increasingly important roles for the structure determination of DPCs [26]. In our previous study, a novel approach was presented for the sub-ppb detection and quantification of DPCs by newly developed inductively coupled plasma mass spectrometry/mass spectrometry (ICPMS/MS) [27]. This method is an effective technique for purifying DPCs.…”