Electron-impact-induced tryptophan molecule fragmentation

Tamulienė, Jelena; Romanova, Liudmila; Vukstich, V. S.; Papp, Alexander; Snegursky, A.V.

doi:10.1140/epjd/e2014-50551-2

Cited by 5 publications

(5 citation statements)

References 25 publications

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“…There was an increase in the tota counts of C9H8N + in the amino acid functionalised samples compared to uncoated sam ples. This correlates to a high-intensity fragment of tryptophan [27,28] which confirme the successful immobilisation of amino acids on the surface of brackets (Figure 4).…”

Section: Tof-simssupporting

confidence: 64%

Bioactive Plasma Coatings on Orthodontic Brackets: In Vitro Metal Ion Release and Cytotoxicity

et al. 2021

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The metal ion release characteristics and biocompatibility of meta-based materials are key factors that influence their use in orthodontics. Although stainless steel-based alloys have gained much interest and use due to their mechanical properties and cost, they are prone to localised attack after prolonged exposure to the hostile oral environment. Metal ions may induce cellular toxicity at high dosages. To circumvent these issues, orthodontic brackets were coated with a functional nano-thin layer of plasma polymer and further immobilised with enantiomers of tryptophan. Analysis of the physicochemical properties confirmed the presence of functional coatings on the surface of the brackets. The quantification of metal ion release using mass spectrometry proved that plasma functionalisation could minimise metal ion release from orthodontic brackets. Furthermore, the biocompatibility of the brackets has been improved after functionalisation. These findings demonstrate that plasma polymer facilitated surface functionalisation of orthodontic brackets is a promising approach to reducing metal toxicity without impacting their bulk properties.

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Section: Tof-simssupporting

confidence: 64%

Bioactive Plasma Coatings on Orthodontic Brackets: In Vitro Metal Ion Release and Cytotoxicity

et al. 2021

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“…The ionization potential of gas phase l -Trp is about 7.5 eV. 65 With solvent stabilization of products, the ionization potential can be decreased by as much as 2.5 eV. 66 The one-photon ionization of aqueous tryptophan and model compounds has been previously reported with 266 nm light in the solvated electron community.…”

Section: Discussionmentioning

confidence: 97%

“…In the absence of an electron acceptor, oxidation of the singlet or triplet state can still occur via direct photoionization to solvent/protein. The ionization potential of gas phase l -Trp is about 7.5 eV . With solvent stabilization of products, the ionization potential can be decreased by as much as 2.5 eV .…”

Section: Discussionmentioning

confidence: 99%

Role of the Triplet State and Protein Dynamics in the Formation and Stability of the Tryptophan Radical in an Apoazurin Mutant

et al. 2022

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The protein, azurin, has enabled the study of the tryptophan radical. Upon UV excitation of tyrosine-deficient apoazurin and in the presence of a Co(III) electron acceptor, the neutral radical (W48•) is formed. The lifetime of W48• in apoazurin is 41 s, which is shorter than the lifetime of several hours in Zn-substituted azurin. Molecular dynamics simulations revealed enhanced fluctuations of apoazurin which likely destabilize W48•. The photophysics of W48 was investigated to probe the precursor state for ET. The phosphorescence intensity was eliminated in the presence of an electron acceptor while the fluorescence was unchanged; this quenching of the phosphorescence is attributed to ET. The kinetics associated with W48• were examined with a model that incorporates intersystem crossing, ET, deprotonation, and decay of the cation radical. The estimated rate constants for ET (6 × 10 6 s –1 ) and deprotonation (3 × 10 5 s –1 ) are in agreement with a photoinduced mechanism where W48• is derived from the triplet state. The triplet as the precursor state for ET was supported by photolysis of apoazurin with 280 nm in the absence and presence of triplet-absorbing 405 nm light. Absorption bands from the neutral radical were observed only in the presence of blue light.

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“…Several structures and fragments of the L-threonine molecule were studied by the Becke's three-parameter hybrid functional applying the non-local correlation provided by the Lee, Yang and Parr (B3LYP) [15] method, which is a representative standard density functional theory (DFT), along with the correlation consistent triple zeta basis (cc-pVTZ) [16]. We have used the abovementioned theoretical methods while studying the fragmentation of other AAs, such as proline, tryptophan and asparagine, induced by low-energy electrons [17][18][19]. The results of theoretical research correspond to the experiment results, indicating that the abovementioned methods are appropriate for studying the fragmentation of AAs.…”

Section: Methodsmentioning

confidence: 99%

On the influence of water on fragmentation of the amino acid L-threonine

Baliulyte

Tamulienė

2019

Open Physics

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The present study describes the fragmentation of the amino acid L-threonine (C4H9NO3) with and without the inclusion of water influence. The fragmentation of the L-threonine molecule was theoretically studied using the Becke’s three-parameter hybrid functional method by applying the non-local correlation provided by Lee, Yang and Parr (B3LYP) with the correlation consistent triple zeta basis (cc-pVTZ). The polarizable continuum model (PCM) was used to evaluate the influence of water. Fragments were selected based on data from mass spectrometry experiments. The chemical compositions of fragments were identified, and the appearance energy was calculated. Based on the obtained results, we can conclude that water affects the appearance energy, the fragment structure and the fragment formation processes.

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Electron-impact-induced tryptophan molecule fragmentation

Cited by 5 publications

References 25 publications

Bioactive Plasma Coatings on Orthodontic Brackets: In Vitro Metal Ion Release and Cytotoxicity

Bioactive Plasma Coatings on Orthodontic Brackets: In Vitro Metal Ion Release and Cytotoxicity

Role of the Triplet State and Protein Dynamics in the Formation and Stability of the Tryptophan Radical in an Apoazurin Mutant

On the influence of water on fragmentation of the amino acid L-threonine

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