Revisiting Fragmentation Reactions of Protonated α-Amino Acids by High-Resolution Electrospray Ionization Tandem Mass Spectrometry with Collision-Induced Dissociation

Zhang, Pengwei; Chan, Wan; Ang, Irene; Wei, Rui; Lam, Melody M. T.; Lei, Kate M K; Poon, Terence Chuen Wai

doi:10.1038/s41598-019-42777-8

Cited by 82 publications

(107 citation statements)

References 23 publications

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“…The neutral loss of 46 amu (H 2 O + CO) led to the MS2 ion at m/z 70 amu. The fragmentation pattern was in agreement with the cyclic amino acid proline [38]. Compound V presented a molecular ion at [M + H] + m/z 132.1 amu.…”

Section: Amino Acids and Derivativessupporting

confidence: 67%

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Iridoids and Amino Acid Derivatives from the Paraguayan Crude Drug Adenocalymma marginatum (ysypó hû)

et al. 2020

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The crude drug ysypó hû (Adenocalymma marginatum DC., Bignoniaceae) is used traditionally by the Guarani of Eastern Paraguayan as a male sexual enhancer. The aim of the present study was to identify the main constituents of the crude drug and to evaluate the in vitro inhibitory activity towards the enzyme phosphodiesterase-5 (PDE-5). The main compounds were isolated by counter-current chromatography (CCC). The metabolites were identified by spectroscopic and spectrometric means. The chemical profiling of the extracts was assessed by high-performance liquid chromatography coupled to mass spectrometry (HPLC-MS/MS). The crude extract and main isolated compounds were tested for their PDE-5 inhibitory activity using commercial kits. The iridoid theviridoside and 4-hydroxy-1-methylproline were isolated as the main constituent of the crude drug. Four chlortheviridoside hexoside derivatives were detected for the first time as natural products. Chemical profiling by HPLC-MS/MS led to the tentative identification of nine iridoids, six phenolics, and five amino acids. The crude extracts and main compounds were inactive towards PDE-5 at concentrations up to 500 µg/mL. Iridoids and amino acid derivatives were the main compounds occurring in the Paraguayan crude drug. The potential of ysypó hû as a male sexual enhancer cannot be discarded, since other mechanisms may be involved.

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Section: Amino Acids and Derivativessupporting

confidence: 67%

“…The neutral loss of 46 amu (H 2 O + CO) led to the MS2 ion at m/z 86.1 amu. The consecutive loss of −17 amu (NH 3 ) was in full agreement with the branched amino acid isoleucine [38]. The HPLC traces are depicted in Figure 4.…”

Section: Amino Acids and Derivativessupporting

confidence: 58%

Iridoids and Amino Acid Derivatives from the Paraguayan Crude Drug Adenocalymma marginatum (ysypó hû)

et al. 2020

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“…In peptides composed by isoleucine or leucine, fragments at m/z 132.02 and 86.09 corresponded, respectively, to protonated leucine/isoleucine and subsequent loss of H 2 O and CO. Finally, the loss of H 2 O and CO in protonated phenylalanine formed the major fragment ion at m/z 120.08 ( 19 ). Assuming that the vesicular components are synthesized within the cells and exported extracellularly, we also analyzed cellular and supernatant extracts.…”

Section: Resultsmentioning

confidence: 99%

Small Molecule Analysis of Extracellular Vesicles Produced by Cryptococcus gattii: Identification of a Tripeptide Controlling Cryptococcal Infection in an Invertebrate Host Model

et al. 2021

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The small molecule (molecular mass <900 Daltons) composition of extracellular vesicles (EVs) produced by the pathogenic fungus Cryptococcus gattii is unknown, which limits the understanding of the functions of cryptococcal EVs. In this study, we analyzed the composition of small molecules in samples obtained from solid cultures of C. gattii by a combination of chromatographic and spectrometric approaches, and untargeted metabolomics. This analysis revealed previously unknown components of EVs, including small peptides with known biological functions in other models. The peptides found in C. gattii EVs had their chemical structure validated by chemical approaches and comparison with authentic standards, and their functions tested in a Galleria mellonella model of cryptococcal infection. One of the vesicular peptides (isoleucine-proline-isoleucine, Ile-Pro-Ile) improved the survival of G. mellonella lethally infected with C. gattii or C. neoformans. These results indicate that small molecules exported in EVs are biologically active in Cryptococcus. Our study is the first to characterize a fungal EV molecule inducing protection, pointing to an immunological potential of extracellular peptides produced by C. gattii.

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“…Elimination of an HCN group has been previously observed in the fragmentation of amino acids and nucleic acids. 33,34 In the indirubin precursor ion, H 2 and F I G U R E 5 Proposed fragmentation mechanism for protonated tryptanthrin (black) and its derivative (green). This study was able to establish an LC/MS method for the analysis of actively transforming metabolites in the fermentation extract of Indigofera.…”

Section: Resultsmentioning

confidence: 99%

Profiling the Philippine Blue: Liquid chromatography/mass spectrometry‐based metabolomics study on Philippine Indigofera

Molino

Junio

2021

Rapid Comm Mass Spectrometry

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Rationale High‐throughput liquid chromatography/mass spectrometry (LC/MS) analysis presents an interesting platform for natural dyes research. A particular example is the assessment of the dynamic changes in fermentation mixtures of Philippine Indigofera, and in the investigation of commercially available indigo prepared using traditional and optimized methods. Methods Leaves from Indigofera tinctoria and Indigofera suffruticosa were subjected to methanolic extraction and aqueous fermentation for 48 h. Indigo powders prepared following 2‐day and 15‐day fermentation were also subjected to profiling using ultra‐high‐performance liquid chromatography/quadrupole time‐of‐flight mass spectrometry (UHPLC/QTOF‐MS). MS2 spectra were annotated through a library search in the community‐curated Global Natural Products Social Molecular Networking (GNPS). Spectra with no library hits in GNPS were annotated by analysis of their fragmentation pathways. Results UHPLC/MS‐based detection and fragmentation analysis led to characterization of leucoindigo and the unreported tryptanthrin intermediate, 5a‐hydroxy‐5,5a‐dihydroindolo[2,1‐b]quinazoline‐6,12‐dione, in the fermentation extract of I. tinctoria leaves. Indigo‐associated metabolites were absent in an Indigofera specimen in Laguna Province, which explained why it did not produce blue dye. Locally produced indigo was abundant in indigotin and indirubin, differentiated based on product ions with the corresponding predicted fragmentation pattern. The relative intensity of indigotin, however, decreased with the traditional process of extended fermentation to produce indigo. Conclusions The study is the first to demonstrate simultaneous MS‐based analysis of reaction intermediates, indigotin dye, side products, and catabolites on actively transforming fermentation extracts of I. tinctoria. New results include annotated mass spectra for leucoindigo, and for the unreported 5a‐hydroxy‐5,5a‐dihydroindolo[2,1‐b]quinazoline‐6,12‐dione, which is probably an intermediate in tryptranthrin synthesis. The proposed fragmentation schemes could guide the annotation of analogous compounds in complex mixtures.

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Revisiting Fragmentation Reactions of Protonated α-Amino Acids by High-Resolution Electrospray Ionization Tandem Mass Spectrometry with Collision-Induced Dissociation

Cited by 82 publications

References 23 publications

Iridoids and Amino Acid Derivatives from the Paraguayan Crude Drug Adenocalymma marginatum (ysypó hû)

Iridoids and Amino Acid Derivatives from the Paraguayan Crude Drug Adenocalymma marginatum (ysypó hû)

Small Molecule Analysis of Extracellular Vesicles Produced by Cryptococcus gattii: Identification of a Tripeptide Controlling Cryptococcal Infection in an Invertebrate Host Model

Profiling the Philippine Blue: Liquid chromatography/mass spectrometry‐based metabolomics study on Philippine Indigofera

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