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Journal of the American Society for Mass Spectrometry

David Nguyen, Leland Mayne, Michael C Phillips, S Walter Englander
The analysis of many hydrogen exchange (HX) experiments depends on knowledge of exchange rates expected for the unstructured protein under the same conditions. We present here some minor adjustments to previously calibrated values and a stringent test of their accuracy. Graphical Abstract ᅟ.
July 18, 2018: Journal of the American Society for Mass Spectrometry
Farshid Mashayekhy Rad, Javier Zurita, Philippe Gilles, Laurens A J Rutgeerts, Ulrika Nilsson, Leopold L Ilag, Caroline Leck
In this article, an analytical methodology to investigate the proteinaceous content in atmospheric size-resolved aerosols collected at the Zeppelin observatory (79 °N, 12 °E) at Ny Ålesund, Svalbard, from September to December 2015, is proposed. Quantitative determination was performed after acidic hydrolysis using ultrahigh-performance liquid chromatography in reversed-phase mode coupled to electrospray ionization tandem mass spectrometry. Chromatographic separation, as well as specificity in the identification, was achieved by derivatization of the amino acids with N-butyl nicotinic acid N-hydroxysuccinimide ester prior to the analysis...
July 17, 2018: Journal of the American Society for Mass Spectrometry
Monica M Schroll, Katelyn R Ludwig, Gabriel J LaBonia, Emily L Herring, Amanda B Hummon
Short-term glucose starvation prior to chemotherapy has the potential to preferentially weaken cancer cells, making them more likely to succumb to treatment, while protecting normal cells. In this study, we used 3D cell cultures of colorectal cancer and assessed the effects of short-term glucose starvation and chemotherapy compared to treatment of either individually. We evaluated both phenotypic changes and protein expression levels. Our findings indicate that the combined treatment results in more significant phenotypic responses, including decreased cell viability and clonogenicity...
July 17, 2018: Journal of the American Society for Mass Spectrometry
Patrick Esch, Sven Heiles
The ability to control the charge state and ionization efficiency of lipids and hydrocarbons by means of in-source Paternò-Büchi functionalization in nano-electrospray ionization mass spectrometry experiments is investigated. Ultraviolet light irradiation of acetylpyridine filled nano-electrospray emitter tips, containing unsaturated analytes, generates protonated lipid and hydrocarbon ions. Comparison of reaction yields and fragment ion abundances of functionalized unsaturated fatty acids indicate that acetylpyridine Paternò-Büchi functionalization allows to readily detect fatty acids and determine double bond positions, but fragmentation efficiency and reactivity depend on double bond position and varies between different acetylpyridine isomers...
July 16, 2018: Journal of the American Society for Mass Spectrometry
Satrajit Chakrabarty, Matthew J DiTucci, Giel Berden, Jos Oomens, Evan R Williams
Gas phase infrared dissociation spectra of the radical cation, deprotonated and protonated forms of the hormone melatonin, and its complexes with alkali (Li+ , Na+ , and K+ ) and alkaline earth metal ions (Mg2+ , Ca2+ , and Sr2+ ) are measured in the spectral range 800-1800 cm-1 . Minimum energy geometries calculated at the B3LYP/LACVP++** level are used to assign structural motifs to absorption bands in the experimental spectra. The melatonin anion is deprotonated at the indole-N. The indole-C linking the amide chain is the most favored protonation site...
July 13, 2018: Journal of the American Society for Mass Spectrometry
Sean P Cleary, Huilin Li, Dhanashri Bagal, Joseph A Loo, Iain D G Campuzano, James S Prell
Native mass spectra of large, polydisperse biomolecules with repeated subunits, such as lipoprotein Nanodiscs, can often be challenging to analyze by conventional methods. The presence of tens of closely spaced, overlapping peaks in these mass spectra can make charge state, total mass, or subunit mass determinations difficult to measure by traditional methods. Recently, we introduced a Fourier Transform-based algorithm that can be used to deconvolve highly congested mass spectra for polydisperse ion populations with repeated subunits and facilitate identification of the charge states, subunit mass, charge-state-specific, and total mass distributions present in the ion population...
July 12, 2018: Journal of the American Society for Mass Spectrometry
Yoon Kyung Choi, Joo Yeon Oh, Sang Yun Han
Due to the known sweet-spot issues that intrinsically arise from inhomogeneous formation of matrix-analyte crystals utilized as samples in matrix-assisted laser desorption ionization (MALDI) mass spectrometry, its reproducibility and thus its applications for quantification have been somewhat limited. In this paper, we report a simple strategy to improve the uniformity of matrix-analyte crystal spots, which we realized by adapting large-area graphene films, i.e., non-inert, interacting surfaces, as target surfaces...
July 11, 2018: Journal of the American Society for Mass Spectrometry
HaiYan Wu, LiPeng Zhang, ZaiYue Zhang, Jie Qian, ShuGuang Zhang, YingJun Zhang, SaiJin Ge, XiaoXu Li
An asymmetric trapping field was generated from an asymmetric half-round rod electrode linear ion trap (A-HreLIT), and its performance of unidirectional ion ejection was studied. Two different asymmetric structures of A-HreLITs were constructed, one rotating y electrode pairs toward an x electrode with an angle θ, and the other stretching one x electrode with a distance α. The center of trapping field was displaced away from the geometrical center of the ion trap, defined to be the midpoint along the axis of y between x electrodes, which leads to unidirectional ion ejection through one x electrode...
July 11, 2018: Journal of the American Society for Mass Spectrometry
H Jamie Kim, O Tara Liyanage, Marina R Mulenos, Elyssia S Gallagher
Characterizing glycans is analytically challenging since glycans are heterogeneous, branched polymers with different three-dimensional conformations. Hydrogen/deuterium exchange-mass spectrometry (HDX-MS) has been used to analyze native conformations and dynamics of biomolecules by measuring the mass increase of analytes as labile protons are replaced with deuterium following exposure to deuterated solvents. The rate of exchange is dependent on the chemical functional group, the presence of hydrogen bonds, pH, temperature, charge, and solvent accessibility...
July 11, 2018: Journal of the American Society for Mass Spectrometry
Christine L Kirkpatrick, Nicole C Parsley, Tessa E Bartges, Madeline E Cooke, Wilaysha S Evans, Lilian R Heil, Thomas J Smith, Leslie M Hicks
In the article "Fungal Secretome Analysis via PepSAVI-MS: Identification of the Bioactive Peptide KP4 from Ustilago maydis", acknowledgement of financial support was inadvertently omitted. The authors apologize for this oversight.
July 11, 2018: Journal of the American Society for Mass Spectrometry
Philippe Massonnet, Jean R N Haler, Gregory Upert, Nicolas Smargiasso, Gilles Mourier, Nicolas Gilles, Loïc Quinton, Edwin De Pauw
Disulfide connectivity in peptides bearing at least two intramolecular disulfide bonds is highly important for the structure and the biological activity of the peptides. In that context, analytical strategies allowing a characterization of the cysteine pairing are of prime interest for chemists, biochemists, and biologists. For that purpose, this study evaluates the potential of MALDI in-source decay (ISD) for characterizing cysteine pairs through the systematic analysis of identical peptides bearing two disulfide bonds, but not the same cysteine connectivity...
July 9, 2018: Journal of the American Society for Mass Spectrometry
Joanna A Hogan, Martin F Jarrold
In charge detection mass spectrometry (CDMS), ions are passed through a detection tube and the m/z ratio and charge are determined for each ion. The uncertainty in the charge and m/z determinations can be dramatically reduced by embedding the detection tube in an electrostatic linear ion trap (ELIT) so that ions oscillate back and forth through the detection tube. The resulting time domain signal can be analyzed by fast Fourier transforms (FFTs). The ion's m/z is proportional to the square of the oscillation frequency, and its charge is derived from the FFT magnitude...
July 9, 2018: Journal of the American Society for Mass Spectrometry
Bojana Opačić, Nathan M Hoffman, Zachary P Gotlib, Brian H Clowers, Peter T A Reilly
With advances in the precision of digital electronics, waveform generation technology has progressed to a state that enables the creation of m/z filters that are purely digitally driven. These advances present new methods of performing mass analyses that provide information from a chemical system that are inherently difficult to achieve by other means. One notable characteristic of digitally driven mass filters is the capacity to transmit ions at m/z ratios that vastly exceed the capabilities of traditional resonant systems...
July 9, 2018: Journal of the American Society for Mass Spectrometry
Joshua T Shipman, Eden P Go, Heather Desaire
Recombinantly expressed proteins are susceptible to oxidation during expression, purification, storage, and analysis; the residue most susceptible to oxidation is methionine. Methionine oxidation can be overestimated using current quantitative analysis methods because oxidation can occur during sample preparation, and researchers often do not use methods that account for this possibility. An experimental strategy had been developed previously to solve this problem through the use of an 18 O-labeled hydrogen peroxide reagent...
July 9, 2018: Journal of the American Society for Mass Spectrometry
Amrita Mitra, Amit Kumar Mandal
Besides multiple life-threatening diseases like lung cancer and cardiovascular disease, cigarette smoking is known to produce hypoxia, a state of inadequate oxygen supply to tissues. Hypoxia plays a pivotal role in the development of chronic obstructive pulmonary disease. Smoking during pregnancy imposes risk for the unborn child. In addition to carbon monoxide, conjugation of para-benzoquinone (pBQ), derived from cigarette smoke, with human hemoglobin (HbA) was also reported to contribute in hypoxia. In fact, conjugation of pBQ is more alarming than carbon monoxide as it is an irreversible covalent modification...
July 2, 2018: Journal of the American Society for Mass Spectrometry
Christopher A Zarzana, Gary S Groenewold, Michael T Benson, James E Delmore, Tetsuya Tsuda, Rika Hagiwara
A new methodology for gas-phase uranium ion formation is described in which UO2 is dissolved in neat N-ethyl,N'-methylimidazolium fluorohydrogenate ionic liquid [EMIm+ ][F(HF)2.3 - ], yielding a blue-green solution. The solution was diluted with acetonitrile and then analyzed by electrospray ionization mass spectrometry. UF6 - (a U(V) species) was observed at m/z = 352, and other than cluster ions derived from the ionic liquid, nothing else was observed. When the sample was analyzed using infusion desorption chemical ionization, UF6 - was the base peak, and it was accompanied by a less intense UF5 - that most likely was formed by elimination of a fluorine radical from UF6 - ...
June 28, 2018: Journal of the American Society for Mass Spectrometry
Piriya Wongkongkathep, Jong Yoon Han, Tae Su Choi, Sheng Yin, Hugh I Kim, Joseph A Loo
Structural characterization of intrinsically disordered proteins (IDPs) has been a major challenge in the field of protein science due to limited capabilities to obtain full-length high-resolution structures. Native ESI-MS with top-down MS was utilized to obtain structural features of protein-ligand binding for the Parkinson's disease-related protein, α-synuclein (αSyn), which is natively unstructured. Binding of heavy metals has been implicated in the accelerated formation of αSyn aggregation. Using high-resolution Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry, native top-down MS with various fragmentation methods, including electron capture dissociation (ECD), collisional activated dissociation (CAD), and multistage tandem MS (MS3 ), deduced the binding sites of cobalt and manganese to the C-terminal region of the protein...
June 27, 2018: Journal of the American Society for Mass Spectrometry
Karolina Sekuła, Dariusz Zuba, Karolina Lorek
Recently, dozens of new psychoactive substances have appeared on the European drug market every year. The most abundant group of these compounds is synthetic cannabinoids. In the first few years of the "legal highs" phenomenon, JWH (John W. Huffman) compounds were especially popular among drug users. However, the group of synthetic cannabinoids is constantly expanding, as new compounds are created by replacing known structural elements with different chemical groups. The problem with the identification of novel substances in forensic laboratories results from the structural similarity of the compounds and the rapid introduction of newer designer drugs on the black market...
June 27, 2018: Journal of the American Society for Mass Spectrometry
Niloofar Abolhasani Khaje, Charles K Mobley, Sandeep K Misra, Lindsey Miller, Zixuan Li, Evgeny Nudler, Joshua S Sharp
Fast photochemical oxidation of proteins (FPOP) may be used to characterize changes in protein structure by measuring differences in the apparent rate of peptide oxidation by hydroxyl radicals. The variability between replicates is high for some peptides and limits the statistical power of the technique, even using modern methods controlling variability in radical dose and quenching. Currently, the root cause of this variability has not been systematically explored, and it is unknown if the major source(s) of variability are structural heterogeneity in samples, remaining irreproducibility in FPOP oxidation, or errors in LC-MS quantification of oxidation...
June 25, 2018: Journal of the American Society for Mass Spectrometry
Yannick Baschung, Loredana Lupu, Adrian Moise, Michael Glocker, Stephan Rawer, Alexander Lazarev, Michael Przybylski
Affinity mass spectrometry using selective proteolytic excision and extraction combined with MALDI and ESI mass spectrometry has been applied to the identification of epitope binding sites of lactose, GalNac, and blood group oligosaccharides in two blood group-specific lectins, human galectin-3 and glycine max lectin. The epitope peptides identified comprise all essential amino acids involved in carbohydrate recognition, in complete agreement with available X-ray structures. Tryptic and chymotryptic digestion of lectins for proteolytic extraction/excision-MS was substantially improved by pressure-enhanced digestion using an automated Barocycler procedure (40 kpsi)...
June 25, 2018: Journal of the American Society for Mass Spectrometry
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