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Voeten RLC, Majeed HA, Bos TS, Somsen GW, Haselberg R. Investigating direct current potentials that affect native protein conformation during trapped ion mobility spectrometry-mass spectrometry. J Mass Spectrom 2024; 59:e5021. [PMID: 38605451 DOI: 10.1002/jms.5021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 10/13/2023] [Accepted: 03/06/2024] [Indexed: 04/13/2024]
Abstract
Trapped ion mobility spectrometry-time-of-flight mass spectrometry (TIMS-TOFMS) has emerged as a tool to study protein conformational states. In TIMS, gas-phase ions are guided across the IM stages by applying direct current (DC) potentials (D1-6), which, however, might induce changes in protein structures through collisional activation. To define conditions for native protein analysis, we evaluated the influence of these DC potentials using the metalloenzyme bovine carbonic anhydrase (BCA) as primary test compound. The variation of DC potentials did not change BCA-ion charge and heme content but affected (relative) charge-state intensities and adduct retention. Constructed extracted-ion mobilograms and corresponding collisional cross-section (CCS) profiles gave useful insights in (alterations of) protein conformational state. For BCA, the D3 and D6 potential (which are applied between the deflection transfer and funnel 1 [F1] and the accumulation exit and the start of the ramp, respectively) had most profound effects, showing multimodal CCS distributions at higher potentials indicating gradual unfolding. The other DC potentials only marginally altered the CCS profiles of BCA. To allow for more general conclusions, five additional proteins of diverse molecular weight and conformational stability were analyzed, and for the main protein charge states, CCS profiles were constructed. Principal component analysis (PCA) of the obtained data showed that D1 and D3 exhibit the highest degree of correlation with the ratio of folded and unfolded protein (F/U) as extracted from the mobilograms obtained per set D potential. The correlation of D6 with F/U and protein charge were similar, and D2, D4, and D5 showed an inverse correlation with F/U but were correlated with protein charge. Although DC boundary values for induced conformational changes appeared protein dependent, a set of DC values could be determined, which assured native analysis of most proteins.
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Affiliation(s)
- Robert L C Voeten
- Division of BioAnalytical Chemistry, Department of Chemistry and Pharmaceutical Sciences, Amsterdam Institute of Molecular and Life Sciences (AIMMS), Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
- Centre for Analytical Sciences Amsterdam (CASA), Amsterdam, The Netherlands
- TI-COAST, Amsterdam, The Netherlands
| | - Hany A Majeed
- Division of BioAnalytical Chemistry, Department of Chemistry and Pharmaceutical Sciences, Amsterdam Institute of Molecular and Life Sciences (AIMMS), Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
- Centre for Analytical Sciences Amsterdam (CASA), Amsterdam, The Netherlands
| | - Tijmen S Bos
- Division of BioAnalytical Chemistry, Department of Chemistry and Pharmaceutical Sciences, Amsterdam Institute of Molecular and Life Sciences (AIMMS), Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
- Centre for Analytical Sciences Amsterdam (CASA), Amsterdam, The Netherlands
| | - Govert W Somsen
- Division of BioAnalytical Chemistry, Department of Chemistry and Pharmaceutical Sciences, Amsterdam Institute of Molecular and Life Sciences (AIMMS), Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
- Centre for Analytical Sciences Amsterdam (CASA), Amsterdam, The Netherlands
| | - Rob Haselberg
- Division of BioAnalytical Chemistry, Department of Chemistry and Pharmaceutical Sciences, Amsterdam Institute of Molecular and Life Sciences (AIMMS), Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
- Centre for Analytical Sciences Amsterdam (CASA), Amsterdam, The Netherlands
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Majeed HA, Bos TS, Voeten RLC, Kranenburg RF, van Asten AC, Somsen GW, Kohler I. Trapped ion mobility mass spectrometry of new psychoactive substances: Isomer-specific identification of ring-substituted cathinones. Anal Chim Acta 2023; 1264:341276. [PMID: 37230720 DOI: 10.1016/j.aca.2023.341276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 04/18/2023] [Accepted: 04/23/2023] [Indexed: 05/27/2023]
Abstract
New psychoactive substances (NPS) are synthetic derivatives of illicit drugs designed to mimic their psychoactive effects. NPS are typically not controlled under drug acts or their legal status depends on their molecular structure. Discriminating isomeric forms of NPS is therefore crucial for forensic laboratories. In this study, a trapped ion mobility spectrometry time-of-flight mass spectrometry (TIMS-TOFMS) approach was developed for the identification of ring-positional isomers of synthetic cathinones, a class of compounds representing two-third of all NPS seized in Europe in 2020. The optimized workflow features narrow ion-trapping regions, mobility calibration by internal reference, and a dedicated data-analysis tool, allowing for accurate relative ion-mobility assessment and high-confidence isomer identification. Ortho-, meta- and para-isomers of methylmethcathinone (MMC) and bicyclic ring isomers of methylone were assigned based on their specific ion mobilities within 5 min, including sample preparation and data analysis. The resolution of two distinct protomers per cathinone isomer added to the confidence in identification. The developed approach was successfully applied to the unambiguous assignment of MMC isomers in confiscated street samples. These findings demonstrate the potential of TIMS-TOFMS for forensic case work requiring fast and highly-confident assignment cathinone-drug isomers in confiscated samples.
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Affiliation(s)
- Hany A Majeed
- Division of Bioanalytical Chemistry, Amsterdam Institute of Molecular and Life Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV, Amsterdam, the Netherlands; Centre for Analytical Sciences Amsterdam (CASA), 1098 XH, Amsterdam, the Netherlands
| | - Tijmen S Bos
- Division of Bioanalytical Chemistry, Amsterdam Institute of Molecular and Life Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV, Amsterdam, the Netherlands; Centre for Analytical Sciences Amsterdam (CASA), 1098 XH, Amsterdam, the Netherlands
| | - Robert L C Voeten
- Division of Bioanalytical Chemistry, Amsterdam Institute of Molecular and Life Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV, Amsterdam, the Netherlands; Centre for Analytical Sciences Amsterdam (CASA), 1098 XH, Amsterdam, the Netherlands
| | - Ruben F Kranenburg
- Centre for Analytical Sciences Amsterdam (CASA), 1098 XH, Amsterdam, the Netherlands; Forensic Laboratory, Unit Amsterdam, Dutch National Police, Kabelweg 25, 1014 BA, Amsterdam, the Netherlands; Van't Hoff Institute for Molecular Sciences, University of Amsterdam, P.O. Box 94157, 1090 GD, Amsterdam, the Netherlands
| | - Arian C van Asten
- Centre for Analytical Sciences Amsterdam (CASA), 1098 XH, Amsterdam, the Netherlands; Van't Hoff Institute for Molecular Sciences, University of Amsterdam, P.O. Box 94157, 1090 GD, Amsterdam, the Netherlands; Co van Ledden Hulsebosch Center (CLHC), Amsterdam Center for Forensic Science and Medicine, P.O. Box 94157, 1090 GD, Amsterdam, the Netherlands
| | - Govert W Somsen
- Division of Bioanalytical Chemistry, Amsterdam Institute of Molecular and Life Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV, Amsterdam, the Netherlands; Centre for Analytical Sciences Amsterdam (CASA), 1098 XH, Amsterdam, the Netherlands
| | - Isabelle Kohler
- Division of Bioanalytical Chemistry, Amsterdam Institute of Molecular and Life Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV, Amsterdam, the Netherlands; Centre for Analytical Sciences Amsterdam (CASA), 1098 XH, Amsterdam, the Netherlands; Co van Ledden Hulsebosch Center (CLHC), Amsterdam Center for Forensic Science and Medicine, P.O. Box 94157, 1090 GD, Amsterdam, the Netherlands.
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Ventouri IK, Malheiro DBA, Voeten RLC, Kok S, Honing M, Somsen GW, Haselberg R. Probing Protein Denaturation during Size-Exclusion Chromatography Using Native Mass Spectrometry. Anal Chem 2020; 92:4292-4300. [PMID: 32107919 PMCID: PMC7081181 DOI: 10.1021/acs.analchem.9b04961] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
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Size-exclusion chromatography
employing aqueous mobile phases with
volatile salts at neutral pH combined with electrospray-ionization
mass spectrometry (SEC-ESI-MS) is a useful tool to study proteins
in their native state. However, whether the applied eluent conditions
actually prevent protein–stationary phase interactions, and/or
protein denaturation, often is not assessed. In this study, the effects
of volatile mobile phase additives on SEC retention and ESI of proteins
were thoroughly investigated. Myoglobin was used as the main model
protein, and eluents of varying ionic strength and pH were applied.
The degree of interaction between protein and stationary phase was
evaluated by calculating the SEC distribution coefficient. Protein-ion
charge state distributions obtained during offline and online native
ESI-MS were used to monitor alterations in protein structure. Interestingly,
most of the supposedly mild eluent compositions induced nonideal SEC
behavior and/or protein unfolding. SEC experiments revealed that the
nature, ionic strength, and pH of the eluent affected protein retention.
Protein–stationary phase interactions were effectively avoided
using ammonium acetate at ionic strengths above 0.1 M. Direct-infusion
ESI-MS showed that the tested volatile eluent salts seem to follow
the Hofmeister series: no denaturation was induced using ammonium
acetate (kosmotropic), whereas ammonium formate and bicarbonate (both
chaotropic) caused structural changes. Using a mobile phase of 0.2
M ammonium acetate (pH 6.9), several proteins (i.e., myoglobin, carbonic
anhydrase, and cytochrome c) could be analyzed by SEC-ESI-MS using
different column chemistries without compromising their native state.
Overall, with SEC-ESI-MS, the effect of nonspecific interactions between
protein and stationary phase on the protein structure can be studied,
even revealing gradual structural differences along a peak.
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Affiliation(s)
- Iro K Ventouri
- Division of Bioanalytical Chemistry, AIMMS Amsterdam Institute of Molecular and Life Sciences, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, The Netherlands.,Centre for Analytical Sciences Amsterdam, 1098XH Amsterdam, The Netherlands.,TI-COAST, 1098 XH Amsterdam, The Netherlands.,Analytical Chemistry Group, van't Hoff Institute for Molecular Sciences, University of Amsterdam, PO Box 94720, 1090 GE Amsterdam, The Netherlands
| | - Daniel B A Malheiro
- Division of Bioanalytical Chemistry, AIMMS Amsterdam Institute of Molecular and Life Sciences, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, The Netherlands.,TI-COAST, 1098 XH Amsterdam, The Netherlands
| | - Robert L C Voeten
- Division of Bioanalytical Chemistry, AIMMS Amsterdam Institute of Molecular and Life Sciences, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, The Netherlands.,Centre for Analytical Sciences Amsterdam, 1098XH Amsterdam, The Netherlands.,TI-COAST, 1098 XH Amsterdam, The Netherlands
| | - Sander Kok
- DSM Materials Science Center, 6167 RD Geleen, The Netherlands
| | - Maarten Honing
- Division of Bioanalytical Chemistry, AIMMS Amsterdam Institute of Molecular and Life Sciences, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, The Netherlands.,DSM Materials Science Center, 6167 RD Geleen, The Netherlands
| | - Govert W Somsen
- Division of Bioanalytical Chemistry, AIMMS Amsterdam Institute of Molecular and Life Sciences, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, The Netherlands.,Centre for Analytical Sciences Amsterdam, 1098XH Amsterdam, The Netherlands
| | - Rob Haselberg
- Division of Bioanalytical Chemistry, AIMMS Amsterdam Institute of Molecular and Life Sciences, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, The Netherlands.,Centre for Analytical Sciences Amsterdam, 1098XH Amsterdam, The Netherlands
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Affiliation(s)
- Robert L C Voeten
- Division of BioAnalytical Chemistry, Department of Chemistry and Pharmaceutical Sciences, Vrije Universiteit Amsterdam , de Boelelaan 1085, 1081 HV Amsterdam, The Netherlands.,TI-COAST , Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Iro K Ventouri
- TI-COAST , Science Park 904, 1098 XH Amsterdam, The Netherlands.,Analytical Chemistry Group, van't Hoff Institute for Molecular Sciences, University of Amsterdam , Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Rob Haselberg
- Division of BioAnalytical Chemistry, Department of Chemistry and Pharmaceutical Sciences, Vrije Universiteit Amsterdam , de Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
| | - Govert W Somsen
- Division of BioAnalytical Chemistry, Department of Chemistry and Pharmaceutical Sciences, Vrije Universiteit Amsterdam , de Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
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