Influence of the alkali metal cation on the fragmentation of monensin in ESI-MS/MS

Cylindrospermopsin (CYN) belongs to a group of toxins produced by several strains of freshwater cyanobacteria. It is a compact zwitterionic molecule composed of a uracil section and a tricyclic guanidinium portion with a primarily hepatotoxic effect. Using low multi-stage and high-resolution mass spectrometry, the gas-phase reactions of this toxin have been investigated. Our data show that collision-induced dissociation (CID) spectra of CYN are dominated by neutral losses, and three major initial fragmentation pathways are clearly distinguishable. Interestingly, comparative analysis of protonated and cationizated molecules showed a significant difference in the balance of the SO3 and terminal ring elimination. These data indicate that the differential ion mobility of H+, Li+, Na+ and K+ leads to different fragmentation pathways, giving rise to mass spectra with different profiles.

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“…Furthermore, a higher atomic mass presumably contributes to hindering the migration of 'R' through an isotopic effect. 23 …”

Section: Resultsmentioning

confidence: 99%

Comparative analysis of the gas‐phase reactions of cylindrospermopsin and the difference in the alkali metal cation mobility

Tomaz

Lopes

Pinto

2008

Rapid Comm Mass Spectrometry

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“…[M+H 2 O+H] + or [M+NH 3 +H] + ) 25 , and in lithium adduct, another alkali metal element. 26,27 The CMF pathway in [M+Na] + fragmentation spectra has not been formally reported and its extent for fragmentation spectra annotation has never been assessed. 28 To better understand the prevalence of SAIC in small molecule fragmentation spectra, the NIST17 spectral library was investigated.…”

Section: Resultsmentioning

confidence: 99%

Mining the NIST Mass Spectral Library Reveals the Extent of Sodium Assisted Inductive Cleavage in Collision-Induced Fragmentation

Ludwig¹,

Broeckling²,

Dorrestein³

et al. 2020

Preprint

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Interpretation and annotation of fragmentation mass spectra strongly depends on our knowledge of collision-induced fragmentation mechanisms. Computational methods for interpretation of fragmentation operate in the boundaries of recognized fragmentation rules. The prevalence of non-sodiated fragment ions in sodiated ion fragmentation spectra is not yet fully recognized by the mass spectrometry community. Here, we investigated the extent of “Sodium Assisted Inductive Cleavage” (SAIC), a charge migration fragmentation occurring in the fragmentation spectra of sodiated precursors. The NIST17 fragmentation library was mined for evidence of SAIC. A substantial amount of fragment ions in sodiated precursor spectra can be linked to SAIC. Thus, this fragmentation mechanism must be considered to allow for accurate interpretation of fragmentation spectra.

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“…MonH and its monovalent metal complexes exhibit a very low solubility in water, but are readily soluble in methanol, ethanol, acetone, or chloroform. These solutions were studied in potentiometric, [36][37][38][39][40][41][42] NMR, [43][44][45][46][47] polarographic, 48 and mass-spectrometric [49][50][51][52][53][54] experiments. Natural polyether ionophores such as lasalocid and salinomycin were studied by circular dichroism (CD) in the near UV range, [55][56][57][58][59] but because of the lack of suitable chromophores this technique was not employed so far for monensin.…”

mentioning

confidence: 99%

Circular Dichroism is Sensitive to Monovalent Cation Binding in Monensin Complexes

et al. 2016

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Monensin is a natural antibiotic that exhibits high affinity to certain metal ions. In order to explore its potential in coordination chemistry, circular dichroism (CD) spectra of monensic acid A (MonH) and its derivatives containing monovalent cations (Li(+) , Na(+) , K(+) , Rb(+) , Ag(+) , and Et4 N(+) ) in methanolic solutions were measured and compared to computational models. Whereas the conventional CD spectroscopy allowed recording of the transitions down to 192 nm, synchrotron radiation circular dichroism (SRCD) revealed other bands in the 178-192 nm wavelength range. CD signs and intensities significantly varied in the studied compounds, in spite of their similar crystal structure. Computational modeling based on the Density Functional Theory (DFT) and continuum solvent model suggests that the solid state monensin structure is largely conserved in the solutions as well. Time-dependent Density Functional Theory (TDDFT) simulations did not allow band-to-band comparison with experimental spectra due to their limited precision, but indicated that the spectral changes were caused by a combination of minor conformational changes upon the monovalent cation binding and a direct involvement of the metal electrons in monensin electronic transitions. Both the experiment and simulations thus show that the CD spectra of monensin complexes are very sensitive to the captured ions and can be used for their discrimination. Chirality 28:420-428, 2016. © 2016 Wiley Periodicals, Inc.

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Influence of the alkali metal cation on the fragmentation of monensin in ESI-MS/MS

Cited by 13 publications

References 15 publications

Comparative analysis of the gas‐phase reactions of cylindrospermopsin and the difference in the alkali metal cation mobility

Comparative analysis of the gas‐phase reactions of cylindrospermopsin and the difference in the alkali metal cation mobility

Mining the NIST Mass Spectral Library Reveals the Extent of Sodium Assisted Inductive Cleavage in Collision-Induced Fragmentation

Circular Dichroism is Sensitive to Monovalent Cation Binding in Monensin Complexes

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