scholarly journals DNA and RNA Telomeric G-Quadruplexes: What Topology Features Can be Inferred from Ion Mobility Mass Spectrometry?

2019 ◽  
Author(s):  
Valentina D’Atri ◽  
Valerie Gabelica
Keyword(s):  
Mass Spectrometry ◽  
Gas Phase ◽  
Ion Mobility Spectrometry ◽  
Ion Mobility ◽  
Native Mass Spectrometry ◽  
Cation Binding ◽  
Telomeric Dna ◽  
Dna And Rna ◽  
G Quadruplex ◽  
Multiple Structures

Maintenance of the telomeres is key to chromosome integrity and cell proliferation. The G-quadruplex structures formed by telomeric DNA and RNA (TTAGGG and UUAGGG repeats, respectively) are key to this process. However, because these sequences are particularly polymorphic, solving high-resolution structures is not always possible, and there is a need for new methodologies to characterize the multiple structures coexisting in solution. In this context, we evaluated whether ion mobility spectrometry coupled to native mass spectrometry could help separate and assign the G-quadruplex topologies. We explored the circular dichroism spectra, multimer formation, cation binding, and ion mobility spectra of several 4-repeat and 8-repeat telomeric DNA and RNA sequences, both in NH<sub>4</sub><sup>+</sup> and in K<sup>+</sup>. In 1 mM K<sup>+</sup> and 100 mM trimethylammonium acetate, all RNAs fold intramolecularly (no multimer). In 8-repeat sequences, the subunits are not independent: in DNA the first subunit disfavors the folding of the second one, whereas in RNA the two subunits fold cooperatively via cation-mediated stacking. Ion mobility spectrometry shows that gas-phase structures keep a memory of the solution ones, but not identical. At the native charge states, the loops can rearrange in a variety of ways (unless they are constrained by pre-formed hydrogen bonds), thereby wrapping the core and masking the strand arrangements. Our study highlights that, to progress towards structural assignment from IM-MS experiments, deeper understanding of the solution-to-gas-phase rearrangement mechanisms is warranted. <br>

scholarly journals DNA and RNA Telomeric G-Quadruplexes: What Topology Features Can be Inferred from Ion Mobility Mass Spectrometry?

2019 ◽  
Author(s):  
Valentina D’Atri ◽  
Valerie Gabelica
Keyword(s):  
Mass Spectrometry ◽  
Gas Phase ◽  
Ion Mobility Spectrometry ◽  
Ion Mobility ◽  
Native Mass Spectrometry ◽  
Cation Binding ◽  
Telomeric Dna ◽  
Dna And Rna ◽  
G Quadruplex ◽  
Multiple Structures

Maintenance of the telomeres is key to chromosome integrity and cell proliferation. The G-quadruplex structures formed by telomeric DNA and RNA (TTAGGG and UUAGGG repeats, respectively) are key to this process. However, because these sequences are particularly polymorphic, solving high-resolution structures is not always possible, and there is a need for new methodologies to characterize the multiple structures coexisting in solution. In this context, we evaluated whether ion mobility spectrometry coupled to native mass spectrometry could help separate and assign the G-quadruplex topologies. We explored the circular dichroism spectra, multimer formation, cation binding, and ion mobility spectra of several 4-repeat and 8-repeat telomeric DNA and RNA sequences, both in NH<sub>4</sub><sup>+</sup> and in K<sup>+</sup>. In 1 mM K<sup>+</sup> and 100 mM trimethylammonium acetate, all RNAs fold intramolecularly (no multimer). In 8-repeat sequences, the subunits are not independent: in DNA the first subunit disfavors the folding of the second one, whereas in RNA the two subunits fold cooperatively via cation-mediated stacking. Ion mobility spectrometry shows that gas-phase structures keep a memory of the solution ones, but not identical. At the native charge states, the loops can rearrange in a variety of ways (unless they are constrained by pre-formed hydrogen bonds), thereby wrapping the core and masking the strand arrangements. Our study highlights that, to progress towards structural assignment from IM-MS experiments, deeper understanding of the solution-to-gas-phase rearrangement mechanisms is warranted. <br>

scholarly journals State-of-the-Art Native Mass Spectrometry and Ion Mobility Methods to Monitor Homogeneous Site-Specific Antibody-Drug Conjugates Synthesis

2021 ◽  
Vol 14 (6) ◽  
pp. 498
Author(s):  
Evolène Deslignière ◽  
Anthony Ehkirch ◽  
Bastiaan L. Duivelshof ◽  
Hanna Toftevall ◽  
Jonathan Sjögren ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gas Phase ◽  
Ion Mobility ◽  
State Of The Art ◽  
Native Mass Spectrometry ◽  
Site Specific ◽  
Drug Conjugates ◽  
Conjugation Process ◽  
Antibody Drug

Antibody-drug conjugates (ADCs) are biotherapeutics consisting of a tumor-targeting monoclonal antibody (mAb) linked covalently to a cytotoxic drug. Early generation ADCs were predominantly obtained through non-selective conjugation methods based on lysine and cysteine residues, resulting in heterogeneous populations with varying drug-to-antibody ratios (DAR). Site-specific conjugation is one of the current challenges in ADC development, allowing for controlled conjugation and production of homogeneous ADCs. We report here the characterization of a site-specific DAR2 ADC generated with the GlyCLICK three-step process, which involves glycan-based enzymatic remodeling and click chemistry, using state-of-the-art native mass spectrometry (nMS) methods. The conjugation process was monitored with size exclusion chromatography coupled to nMS (SEC-nMS), which offered a straightforward identification and quantification of all reaction products, providing a direct snapshot of the ADC homogeneity. Benefits of SEC-nMS were further demonstrated for forced degradation studies, for which fragments generated upon thermal stress were clearly identified, with no deconjugation of the drug linker observed for the T-GlyGLICK-DM1 ADC. Lastly, innovative ion mobility-based collision-induced unfolding (CIU) approaches were used to assess the gas-phase behavior of compounds along the conjugation process, highlighting an increased resistance of the mAb against gas-phase unfolding upon drug conjugation. Altogether, these state-of-the-art nMS methods represent innovative approaches to investigate drug loading and distribution of last generation ADCs, their evolution during the bioconjugation process and their impact on gas-phase stabilities. We envision nMS and CIU methods to improve the conformational characterization of next generation-empowered mAb-derived products such as engineered nanobodies, bispecific ADCs or immunocytokines.

scholarly journals Exploring the conformational landscape of a lanthipeptide synthetase using native mass spectrometry

2020 ◽  
Author(s):  
Nuwani W. Weerasinghe ◽  
Yeganeh Habibi ◽  
Kevin A. Uggowitzer ◽  
Christopher J. Thibodeaux
Keyword(s):  
Mass Spectrometry ◽  
Gas Phase ◽  
Conformational Changes ◽  
Ion Mobility ◽  
Peptide Binding ◽  
Native Mass Spectrometry ◽  
Order Structure ◽  
Conformational Sampling ◽  
Precursor Peptide ◽  
Conformational Landscape

AbstractLanthipeptides are ribosomally-synthesized and post-translationally modified peptide (RiPP) natural products that are biosynthesized in a multistep maturation process by enzymes (lanthipeptide synthetases) that possess relaxed substrate specificity. Recent evidence has suggested that some lanthipeptide synthetases are structurally dynamic enzymes that are allosterically activated by precursor peptide binding, and that conformational sampling of the enzyme-peptide complex may play an important role in defining the efficiency and sequence of biosynthetic events. These “biophysical” processes, while critical for defining the activity and function of the synthetase, remain very challenging to study with existing methodologies. Herein, we show that native nanoelectrospray ionization coupled to ion mobility mass spectrometry (nanoESI-IM-MS) provides a powerful and sensitive means for investigating the conformational landscapes and intermolecular interactions of lanthipeptide synthetases. Namely, we demonstrate that the class II lanthipeptide synthetase (HalM2) and its non-covalent complex with the cognate HalA2 precursor peptide can be delivered into the gas phase in a manner that preserves native structures and intermolecular enzyme-peptide contacts. Moreover, gas phase ion mobility studies of the natively-folded ions demonstrate that peptide binding and mutations to dynamic structural elements of HalM2 alter the conformational landscape of the enzyme, and that the precursor peptide itself exhibits higher order structure in the mass spectrometer. Cumulatively, these data support previous claims that lanthipeptide synthetases are structurally dynamic enzymes that undergo functionally relevant conformational changes in response to precursor peptide binding. This work establishes nanoESI-IM-MS as a versatile approach for unraveling the relationships between protein structure and biochemical function in RiPP biosynthetic systems.

scholarly journals DNA and RNA telomeric G-quadruplexes: what topology features can be inferred from ion mobility mass spectrometry?

The Analyst ◽  
2019 ◽  
Vol 144 (20) ◽  
pp. 6074-6088 ◽  
Author(s):  
Valentina D'Atri ◽  
Valérie Gabelica
Keyword(s):  
Mass Spectrometry ◽  
Gas Phase ◽  
Ion Mobility ◽  
Ion Mobility Mass Spectrometry ◽  
Dna And Rna

Besides strand and cation stoichiometry, IM-MS reports on folding, but ion mobility interpretation must consider gas-phase compaction in native conditions.

Software for the Analysis and Interpretation of Native Mass Spectrometry Data

2019 ◽  
Author(s):  
Timothy Allison ◽  
Perdita Barran ◽  
Justin Benesch ◽  
Sarah Cianferani ◽  
Matteo Degiacomi ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Ion Mobility Spectrometry ◽  
Ion Mobility ◽  
Protein Complexes ◽  
Native Mass Spectrometry ◽  
Mass Spectrometry Data ◽  
Full Potential ◽  
Research Groups ◽  
Future Developments ◽  
New Instrumentation

<div><div><div><p>The last few years have seen a dramatic increase in applications of native mass and ion mobility spectrometry, especially for the study of proteins and protein complexes. This increase has been catalysed by the availability of commercial instrumentation capable of carrying out such analyses. Like in most fields, however, the software to process the data generated from new instrumentation lags behind. Recently, a number of research groups have started addressing this by developing software, but further improvements are still required in order to realise the full potential of the datasets generated. Here we describe practical aspects as well as challenges in processing native mass spectrometry (MS) and ion mobility-MS datasets, and provide a brief overview of currently available tools. We then set out our vision of future developments that would bring the community together and lead to the development of a common platform to expedite future computational developments, provide standardised processing approaches and serve as a location for the deposition of data for this emerging field.</p></div></div></div>

scholarly journals Ion‐Mobility Spectrometry Can Assign Exact Fucosyl Positions in Glycans and Prevent Misinterpretation of Mass‐Spectrometry Data After Gas‐Phase Rearrangement

2019 ◽  
Vol 131 (49) ◽  
pp. 17780-17784
Author(s):  
Javier Sastre Toraño ◽  
Ivan A. Gagarinov ◽  
Gaël M. Vos ◽  
Frederik Broszeit ◽  
Apoorva D. Srivastava ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gas Phase ◽  
Ion Mobility Spectrometry ◽  
Ion Mobility ◽  
Mass Spectrometry Data
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