The Development and Utilization of the Periodic Focusing Ion Funnel

Ion mobility-mass spectrometry (IM-MS) provides gas phase, size-based separation, on an ultrafast timescale (μs-ms). With the incorporation of electrospray ionization, IM-MS is a valuable tool to investigate conformations of biological molecule ions that can be representative of their solution-phase structure. In some cases, evaporative cooling during ESI can kinetically trap these solution-phase structures in local minima along the potential energy surface. However, if the internal energy of the ion is increased via collisional activation, these solution-phase structures can be readily converted to an energetically preferred, gas-phase structure. Radio frequency (RF) confining devices, such as the RF ion funnel, are typically used to increase ion transmission in IM-MS measurements; however, these devices can lead to collisional activation and structural rearrangement due to high voltage oscillation amplitudes (Vp-p). Recently, periodic focusing ion mobility spectrometry (PF IMS) has been shown to provide comparable radial confinement, while utilizing reduced radial electric fields Vp-p as compared to the RF ion funnel. Work presented herein describes the development and characterization of a periodic focusing ion funnel (PF IF) that is capable of increasing ion transmission while being able to preserve nascent conformer distributions and subsequently inducing structural rearrangement. The utility of the PF IF is demonstrated with the neuropeptide Substance P (SP), as it provides a model for studying the structural effects of collisional activation due to the presence of both a kinetically trapped and gas-phase conformer, denoted ASP and BSP, respectively. By increasing the internal energy of [SP + 3H]^3+ ions, ASP is quantitatively converted to BSP, which is consistent with ASP being a kinetically trapped conformer and BSP being a gas-phase conformer. The collision cross section and mobility resolution of the ASP suggests that it is comprised of a broad distribution of compact globular conformations. Intramolecular solvation appears to stabilize the compacted structure of ASP in the gas-phase; however, as the ion’s internal energy increases, these noncovalent interactions are disrupted and the peptide converts into the gas-phase conformation. Mutations of various amino acid residues of SP provide a means of identifying these interactions and their effect on the stability of the kinetically trapped conformers

Characterization of an Omnitrap-Orbitrap platform equipped with infrared multiphoton dissociation, ultraviolet photodissociation, and electron capture dissociation for the analysis of peptides and proteins

We describe an instrument configuration based on the Orbitrap Exploris 480 mass spectrometer that has been coupled to an Omnitrap platform. The Omnitrap possesses three distinct ion-activation regions that can be used to perform resonant-based collision-induced dissociation, several forms of electron-associated fragmentation, and ultraviolet photodissociation. Each section can also be combined with infrared multiphoton dissociation. In this work, we demonstrate all these modes of operation in a range of peptides and proteins. The results show that this instrument configuration produces similar data to previous implementations of each activation technique and at similar efficiency levels. We demonstrate that this unique instrument configuration is extremely versatile for the investigation of polypeptides

A preparative mass spectrometer to deposit intact large native protein complexes

Electrospray ion-beam deposition (ES-IBD) is a versatile tool to study the structure and reactivity of molecules from small metal clusters to large protein assemblies. It brings molecules gently into the gas phase, where they can be accurately manipulated and purified, followed by controlled deposition onto various substrates. In combination with imaging techniques, direct structural information on well-defined molecules can be obtained, which is essential to test and interpret results from indirect mass spectrometry techniques. To date, ion-beam deposition experiments are limited to a small number of custom instruments worldwide, and there are no commercial alternatives. Here we present a module that adds ion-beam deposition capabilities to a popular commercial MS platform (Thermo Scientific Q Exactive UHMR mass spectrometer). This combination significantly reduces the overhead associated with custom instruments, while benefiting from established high performance and reliability. We present current performance characteristics including beam intensity, landing-energy control, and deposition spot size for a broad range of molecules. In combination with atomic force microscopy (AFM) and transmission electron microscopy (TEM), we distinguish near-native from unfolded proteins and show retention of the native shape of protein assemblies after dehydration and deposition. Further, we use an enzymatic assay to quantify the activity of a noncovalent protein complex after deposition on a dry surface. Together, these results not only indicate a great potential of ES-IBD for applications in structural biology, but also outline the challenges that need to be solved for it to reach its full potential

The 2016 Colorado Health Report Card: Celebrating a Decade of Data

This report is an annual update examining the current status of health, health care and health coverage in Colorado. The Health Report Card provides a benchmark for measuring progress on some of the state's most pressing health issues across 38 key health indicators and through five life stages. This year, we celebrate the Health Report Card's 10th anniversary and unveil 10-year trends on where we've made progress and challenges we continue to face. Learn how a decade of data can inform policy solutions to help make Colorado the healthiest state in the nation

Frequency chasing of individual megadalton ions in an Orbitrap analyser improves precision of analysis in single-molecule mass spectrometry

To enhance the performance of charge-detection mass spectrometry, we investigated the behaviour of macromolecular single ions on their paths towards and within the Orbitrap analyser. Ions with a mass beyond one megadalton reach a plateau of stability and can be successfully trapped for seconds, travelling a path length of multiple kilometres, thereby enabling precise mass analysis with an effective resolution of greater than 100,000 at a mass-to-charge ratio of 35,000. Through monitoring the frequency of individual ions, we show that these high-mass ions, rather than being lost from the trap, can gradually lose residual solvent molecules and, in rare cases, a single elementary charge. We also demonstrate that the frequency drift of single ions due to desolvation and charge stripping can be corrected, which improves the effective ion sampling 23-fold and gives a twofold improvement in mass precision and resolution. [Figure not available: see fulltext.

Do foraging ecology and contaminants interactively predict parenting hormone levels in common eider?

Global climate change is causing abiotic shifts such as higher air and ocean temperatures, and disappearing sea ice in Arctic ecosystems. These changes influence Arctic-breeding seabird foraging ecology by altering prey availability and selection, affecting individual body condition, reproductive success, and exposure to contaminants such as mercury (Hg). The cumulative effects of alterations to foraging ecology and Hg exposure may interactively alter the secretion of key reproductive hormones such as prolactin (PRL), important for parental attachment to eggs and offspring and overall reproductive success. However, more research is needed to investigate the relationships between these potential links. Using data collected from 106 incubating female common eiders (Somateria mollissima) at six Arctic and sub-Arctic colonies, we examined whether the relationship between individual foraging ecology (assessed using δ13C, δ15N) and total Hg (THg) exposure predicted PRL levels. We found a significant, complex interaction between δ13C, δ15N and THg on PRL, suggesting that individuals cumulatively foraging at lower trophic levels, in phytoplankton-dominant environments, and with the highest THg levels had the most constant significant relationship PRL levels. Cumulatively, these three interactive variables resulted in lowered PRL. Overall, results demonstrate the potential downstream and cumulative implications of environmentally induced changes in foraging ecology, in combination with THg exposure, on hormones known to influence reproductive success in seabirds. These findings are notable in the context of continuing environmental and food web changes in Arctic systems, which may make seabird populations more susceptible to ongoing stressors. Stable isotopes Carbon-13 Nitrogen-15 Mercury Seabird ArcticacceptedVersio

Corrigendum to “Environmental and life-history factors influence inter-colony multidimensional niche metrics of a breeding Arctic marine bird” [Sci. Total Environ. 796 (2021) 148935] (Science of the Total Environment (2021) 796, (S0048969721040079), (10.1016/j.scitotenv.2021.148935))

The authors regret that the printed version of the above article contained an omission of an individual deserving of co-authorship. The correct and final version follows. The authors would like to apologise for any inconvenience caused. \u3c Reyd A. Smith1⁎, David J. Yurkowski2, Kyle J.L. Parkinson1, Jérôme Fort3, Holly L. Hennin4, H. Grant Gilchrist4, Keith A. Hobson5, Mark L. Mallory6, Paco Bustamante3, Jóhannis Danielsen7, Svend E. Garbus8, Sveinn A. Hanssen9, Jón Einar Jónsson10, Christopher J. Latty11, Ellen Magnúsdóttir10, Børge Moe9, Glen J. Parsons12, Christian Sonne8, Grigori Tertitski13, and Oliver P. Love1\u3e Windsor, Windsor, Ontario, Canada, N9B 3P4 2 Fisheries and Oceans Canada, Winnipeg, Manitoba, Canada, R3T 2N6 3 Littoral, Environnement et Sociétés (LIENSs), UMR 7266 CNRS – La Rochelle University, La Rochelle, France, FR-17000 4 Environment and Climate Change Canada, Ottawa, Ontario, Canada, K0A 1H0. 5 Western University, London, Ontario, Canada, N6A 3K7 6Acadia University, Wolfville, Nova Scotia, Canada, B4P 2R6 7 Faroe Marine Research Institute, Tórshavn, Faroe Islands, FO-110 8 Aarhus University, Roskilde, Denmark, DK-4000 9 Norwegian Institute for Nature Research, Tromsø, Norway, N-9296 10 University of Iceland\u27s Research Centre at Snæfellsnes, Hafnargata 3, 340, Stykkishólmur, Iceland 11 Arctic National Wildlife Refuge, U.S. Fish and Wildlife Service, Fairbanks, Alaska, United States, 99701 12 Nova Scotia Department of Lands and Forestry, Kentville, Nova Scotia, Canada, B4N 4E5 13 Institute of Geography of the Russian Academy of Sciences, Moscow, Russia, 119017\u3

An Orbitrap/Time-of-Flight Mass Spectrometer for Photofragment Ion Imaging and High-Resolution Mass Analysis of Native Macromolecular Assemblies

We discuss the design, development, and evaluation of an Orbitrap/time-of-flight (TOF) mass spectrometry (MS)-based instrument with integrated UV photodissociation (UVPD) and time/mass-to-charge ratio ( m/ z)-resolved imaging for the comprehensive study of the higher-order molecular structure of macromolecular assemblies (MMAs). A bespoke TOF analyzer has been coupled to the higher-energy collisional dissociation cell of an ultrahigh mass range hybrid quadrupole-Orbitrap MS. A 193 nm excimer laser was employed to photofragment MMA ions. A combination of microchannel plates (MCPs)-Timepix (TPX) quad and MCPs-phosphor screen-TPX3CAM assemblies have been used as axial and orthogonal imaging detectors, respectively. The instrument can operate in four different modes, where the UVPD-generated fragment ions from the native MMA ions can be measured with high-mass resolution or imaged in a mass-resolved manner to reveal the relative positions of the UVPD fragments postdissociation. This information is intended to be utilized for retrieving higher-order molecular structural details that include the conformation, subunit stoichiometry, and molecular interactions as well as to understand the dissociation dynamics of the MMAs in the gas phase