Spermine Binding to Parkinson’s Protein α-Synuclein and Its Disease-Related A30P and A53T Mutants

Aggregation of α-synuclein (α-syn), a protein implicated in Parkinson’s disease (PD), is believed to progress through formation of a partially folded intermediate. Using nanoelectrospray ionization (nano-ESI) mass spectrometry combined with ion mobility measurements we found evidence for a highly compact partially folded family of structures for α-syn and its disease-related A53T mutant with net charges of −6, −7, and −8. For the other early onset PD mutant, A30P, this highly compact population was only evident when the protein had a net charge of −6. When bound to spermine near physiologic pH, all three proteins underwent a charge reduction from the favored solution charge state of −10 to a net charge of −6. This charge reduction is accompanied by a dramatic size reduction of about a factor of 2 (cross section of 2600 Å^2 (−10 charge state) down to 1430 Å^2 (−6 charge state)). We conclude that spermine increases the aggregation rate of α-syn by inducing a collapsed conformation, which then proceeds to form aggregates

Analysis of Synthetic Cannabinoids Using High-Resolution Mass Spectrometry and Mass Defect Filtering: Implications for Nontargeted Screening of Designer Drugs

Detection of new designer drugs remains an analytical challenge because of the ability of manufacturers to rapidly substitute closely related analogs for banned substances. Traditional targeted mass spectrometry methods rely on library searches, known masses, or multiple reaction monitoring (MRM) transitions and are therefore often unable to detect or identify recently discovered or yet unreported designer drug analogs. Here, high-resolution mass spectrometry in conjunction with mass defect filtering is presented as a method for nontargeted analysis to detect both known and novel analogs of designer drugs. The technique is applied in depth to a family of designer drugs composed of indole-derived synthetic cannabinoids closely related to JWH-018, a substance recently controlled in the United States. A single mass defect filter with a 50 mDa window encompasses over 80% of all currently published structures in this family. Searching for precursor ions of common fragment ions enables detection of compounds with mass defects that fall outside the range of mass defect filter parameters. Application of a mass defect filter to fragment ions prior to precursor ion searching increases the breadth of analogs that can be detected. The combined approach defines a broad-spectrum search for related molecules

Associations between opioid overdose deaths and drugs confiscated by law enforcement and submitted to crime laboratories for analysis, United States, 2014–2019: an observational studyResearch in context

Summary: Background: The overdose epidemic in the United States (US) continues to generate unprecedented levels of mortality. There is urgent need for a national data system capable of yielding high-quality, timely, and actionable information on existing and emerging drugs. Public health researchers have started using law enforcement forensic laboratory data to obtain surveillance information on illicit drugs. This study is the first to use drug reports from the entire US to examine correlations between a changing drug supply and increasing opioid-involved overdose deaths (OOD) on a national scale. Methods: This study is observational and investigates associations between law enforcement drug reports and OOD for the US from 2014 to 2019. OOD data are from the Centers for Disease Control and Prevention’s National Vital Statistics System restricted-use multiple cause of death files. The US Drug Enforcement Administration’s National Forensic Laboratory Information System (NFLIS) contains forensic laboratory–tested drug exhibit information for the entire US (NFLIS-Drug). Counts of forensic laboratory reports and OOD were aggregated for each state by month, quarter, and year. A difference-in-differences framework was used to estimate contemporaneous and lagged associations. Findings: Between 2014 and 2019 in the US, 249,522 OOD were reported, with the annual number nearly doubling from 28,723 to 50,179. OOD involving illicitly manufactured fentanyls (IMF) also increased substantially during this period, from 19.4% to 72.9%. In addition, 3,817,438 forensic laboratory reports in the US that were reported to NFLIS-Drug contained an opioid, stimulant, or benzodiazepine. Reports of fentanyl and fentanyl-related compounds (FFRC) had the strongest association with OOD. Each additional FFRC exhibit was associated with a 2.97% (95% CI: 1.7%, 4.1%) increase in OOD per 100,000 persons per quarter. Interpretation: Adding to the emerging consensus, protracted growth in IMF supply was more strongly associated with OOD than all other illicit drugs reported to NFLIS-Drug over the study time period. Findings demonstrate NFLIS-Drug data usefulness for research that require proxy indicators for the illicit drugs supply. A concerted effort between public health and public safety to make NFLIS-Drug more timely could strengthen its utility as a national, public health, drug surveillance system. Funding: Sangeetha Arctic Slope Mission Services, LLC, ASMS Contract No. ASM5-00017

Characterization of phosphorylated peptides using traveling wave-based and drift cell ion mobility mass spectrometry

Phosphorylation is one the most studied and important post translational modifications. Nano electrospray mass spectrometry coupled with traveling wave (T-Wave)-based ion mobility has been used to filter for phosphorylated peptides in tryptic protein digests. T-Wave parameters have been optimized to maximize the separation between phosphorylated and non-phosphorylated peptides. A method to calibrate the T-Wave device, to provide estimates of collision cross sections, is presented, and these estimates are in excellent agreement with values obtained on drift cell instrumentation. Phosphorylated peptides have smaller cross sections which enables their separation from non-phosphorylated peptides of the same m/z. Post-mobility fragmentation is used to obtain the primary sequence for peptides of interest. This approach is shown to have potential as an additional screen for phosphorylated peptides, where up to 40% of observed peptides can be eliminated from the study

Characterization of simple isomeric oligosaccharides and the rapid separation of glycan mixtures by ion mobility mass spectrometry

Ion mobility techniques, using both traveling wave-based technology and standard drift tube methods, along with molecular modeling were used to examine the gas-phase conformational properties of a series of isomeric oligosaccharides and hydrazine-released N-linked glycans from various sources. Electrospray ionization was used to generate H+ and Na+ adducts of oligosaccharides as well as Na+ and H2PO4- adducts of released N-linked glycans. The ion mobility mass spectrometry techniques were used to separate the isomeric oligosaccharides and the glycan mixtures. Good agreement was obtained between the theoretical and measured collision cross-sections. Glycans common to each glycoprotein were observed to have the same arrival time distribution independent of their source. In some cases support for multiple isomers was observed which correlated well with evidence obtained, where possible, from other experimental techniques. The sensitivity of the traveling wave ion mobility spectrometry (TWIMS) technique, together with the rapid experimental timescale, reproducibility and high information content make this an attractive approach for the characterization of complex mixtures of glycans released from glycoproteins. Successful calibration of the TWIMS arrival times/cross-sections was demonstrated using data from the drift tube instrument. (C) 2009 Elsevier B.V. All rights reserved