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Grossert JS, Crowell AMJ, Boschi D, Lolli ML, White RL. Tandem mass spectrometry of homologous 3-hydroxyfurazan and nitrile amino acids: Analysis of cooperative interactions and fragmentation processes. JOURNAL OF MASS SPECTROMETRY : JMS 2024; 59:e5043. [PMID: 38789127 DOI: 10.1002/jms.5043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Revised: 04/23/2024] [Accepted: 05/06/2024] [Indexed: 05/26/2024]
Abstract
The assignment of structure by tandem mass spectrometry (MS/MS) relies on the interpretation of the fragmentation behavior of gas-phase ions. Mass spectra were acquired for a series of heterocyclic mimetics of acidic amino acids and a related series of nitrile amino acids. All amino acids were readily protonated or deprotonated by electrospray ionization (ESI), and distinctive fragmentation processes were observed when the ions were subjected to collision-induced dissociation (CID). The deprotonated heterocycles showed bond cleavages of the 3-hydroxyfurazan ring with formation of oxoisocyanate and the complementary deprotonated nitrile amino acid. Further fragmentation of the deprotonated nitrile amino acids was greatly dependent on the length of the alkyl nitrile side chain. Competing losses of CO2 versus HCN occurred from α-cyanoglycinate (shortest chain), whereas water was lost from 2-amino-5-cyanopentanoate (longest chain). Interestingly, loss of acrylonitrile by a McLafferty-type fragmentation process was detected for 2-amino-4-cyanobutanoate, and several competing processes were observed for β-cyanoalanate. In one process, cyanide ion was formed either by consecutive losses of ammonia, carbon dioxide, and acetylene or by a one-step decarboxylative elimination. In another, complementary ions were obtained from β-cyanoalanate by loss of acetonitrile or HN=CHCO2H. Fragmentation of the protonated 3-hydroxyfurazan and nitrile amino acids resulted in the cumulative loss (H2O + CO), a loss that is commonly observed for protonated aliphatic α-amino acids. Overall, the distinct fragmentation behavior of the multifunctional 3-hydroxyfurazan amino acids correlated with the charged site, whereas fragmentations of the deprotonated nitrile amino acids showed cooperative interactions between the nitrile and the carboxylate groups.
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Affiliation(s)
- J Stuart Grossert
- Department of Chemistry, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Andrew M J Crowell
- Department of Chemistry, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Donatella Boschi
- Dipartimento di Scienza e Tecnologia del Farmaco (DSTF), Università degli Studi di Torino, Torino, Italy
| | - Marco L Lolli
- Dipartimento di Scienza e Tecnologia del Farmaco (DSTF), Università degli Studi di Torino, Torino, Italy
| | - Robert L White
- Department of Chemistry, Dalhousie University, Halifax, Nova Scotia, Canada
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Grossert JS, Boschi D, Lolli ML, White RL. Intramolecular interactions and the neutral loss of ammonia from collisionally activated, protonated ω-aminoalkyl-3-hydroxyfurazans. EUROPEAN JOURNAL OF MASS SPECTROMETRY (CHICHESTER, ENGLAND) 2024; 30:38-46. [PMID: 37974410 PMCID: PMC10809737 DOI: 10.1177/14690667231214672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 10/31/2023] [Indexed: 11/19/2023]
Abstract
Gas phase fragmentation reactions of monoprotonated 4-(3-aminopropyl)- and 4-(4-aminobutyl)-3-hydroxyfurazan were investigated to examine potential interactions between functional groups. The two heterocyclic alkyl amines were ionized by electrospray ionization (ESI, positive mode) and fragmented using tandem mass spectrometry (MS/MS). The fragmentation pathways were characterized using pseudo MS3 experiments, precursor-ion scans, and density functional computations. For both heterocyclic ions, loss of ammonia was the only fragmentation process observed at low collision energies. Computational analysis indicated that the most feasible mechanism was intramolecular nucleophilic displacement of ammonia from the protonated ω-aminoalkyl side chain by N5 of the furazan ring. The alkylated nitrogen in the resulting bicyclic product ion facilitated N-O bond cleavage; subsequent neutral losses of nitric oxide (NO) and carbon monoxide (CO) occurred by homolytic bond cleavages. Next in the multistep sequence, neutral loss of ethylene from a radical cation was observed. A less favorable, competing fragmentation pathway of protonated 4-(3-aminopropyl)-3-hydroxyfurazan was consistent with cleavage of the 3-hydroxyfurazan ring and losses of NO and CO. Overall, the similar fragmentation behavior found for protonated 4-(3-aminopropyl)- and 4-(4-aminobutyl)-3-hydroxyfurazan differed from that previously characterized for furazan analogs with shorter alkyl chains. These observations demonstrate that a small change in the structure of multifunctional, heterocyclic alkyl amines may significantly influence interactions between distinct functional groups and the nature of the fragmentation process.
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Affiliation(s)
- J. Stuart Grossert
- Department of Chemistry, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Donatella Boschi
- Dipartimento di Scienza e Tecnologia del Farmaco (DSTF), Università degli Studi di Torino, Torino, Italy
| | - Marco L. Lolli
- Dipartimento di Scienza e Tecnologia del Farmaco (DSTF), Università degli Studi di Torino, Torino, Italy
| | - Robert L. White
- Department of Chemistry, Dalhousie University, Halifax, Nova Scotia, Canada
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Dihydroorotate dehydrogenase inhibitors in anti-infective drug research. Eur J Med Chem 2019; 183:111681. [PMID: 31557612 DOI: 10.1016/j.ejmech.2019.111681] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Revised: 08/01/2019] [Accepted: 09/05/2019] [Indexed: 01/08/2023]
Abstract
Pyrimidines are essential for the cell survival and proliferation of living parasitic organisms, such as Helicobacter pylori, Plasmodium falciparum and Schistosoma mansoni, that are able to impact upon human health. Pyrimidine building blocks, in human cells, are synthesised via both de novo biosynthesis and salvage pathways, the latter of which is an effective way of recycling pre-existing nucleotides. As many parasitic organisms lack pyrimidine salvage pathways for pyrimidine nucleotides, blocking de novo biosynthesis is seen as an effective therapeutic means to selectively target the parasite without effecting the human host. Dihydroorotate dehydrogenase (DHODH), which is involved in the de novo biosynthesis of pyrimidines, is a validated target for anti-infective drug research. Recent advances in the DHODH microorganism field are discussed herein, as is the potential for the development of DHODH-targeted therapeutics.
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Sanchez E, Artuso E, Lombardi C, Visentin I, Lace B, Saeed W, Lolli ML, Kobauri P, Ali Z, spyrakis F, Cubas P, Cardinale F, Prandi C. Structure-activity relationships of strigolactones via a novel, quantitative in planta bioassay. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:2333-2343. [PMID: 29554337 PMCID: PMC5913603 DOI: 10.1093/jxb/ery092] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 02/27/2018] [Indexed: 06/01/2023]
Abstract
Strigolactones (SLs) are plant hormones with various functions in development, responses to stress, and interactions with (micro)organisms in the rhizosphere, including with seeds of parasitic plants. Their perception for hormonal functions requires an α,β-hydrolase belonging to the D14 clade in higher plants; perception of host-produced SLs by parasitic seeds relies on similar but phylogenetically distinct proteins (D14-like). D14 and D14-like proteins are peculiar receptors, because they cleave SLs before undergoing a conformational change that elicits downstream events. Structure-activity relationship data show that the butenolide D-ring is crucial for bioactivity. We applied a bioisosteric approach to the structure of SLs by synthetizing analogues and mimics of natural SLs in which the D-ring was changed from a butenolide to a lactam and then evaluating their bioactivity. This was done by using a novel bioassay based on Arabidopsis transgenic lines expressing AtD14 fused to firefly luciferase, in parallel with the quantification of germination-inducing activity on parasitic seeds. The results obtained showed that the in planta bioassay is robust and quantitative, and thus can be confidently added to the SL-survey toolbox. The results also showed that modification of the butenolide ring into a lactam one significantly hampers the biological activity exhibited by SLs possessing a canonical lactonic D-ring.
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Affiliation(s)
- Elena Sanchez
- Centro Nacional de Biotecnología-CSIC, Plant Molecular Genetics Department, C/ Darwin, Campus UAM, Madrid, Spain
| | - Emma Artuso
- Department of Chemistry, University of Turin, via P. Giuria Turin, Italy
| | - Chiara Lombardi
- Centro Nacional de Biotecnología-CSIC, Plant Molecular Genetics Department, C/ Darwin, Campus UAM, Madrid, Spain
| | - Ivan Visentin
- Department of Agricultural, Forestry and Food Science, Largo P. Braccini, Grugliasco (TO), Italy
| | - Beatrice Lace
- Centro Nacional de Biotecnología-CSIC, Plant Molecular Genetics Department, C/ Darwin, Campus UAM, Madrid, Spain
- University of Freiburg, Faculty of Biology, Cell Biology, Schänzlestr., Freiburg, Germany
| | - Wajeeha Saeed
- Department of Agricultural, Forestry and Food Science, Largo P. Braccini, Grugliasco (TO), Italy
- Department of Biosciences, COMSATS Institute of Information Technology, Islamabad, Pakistan
| | - Marco L Lolli
- Department of Drug Science and Technology, University of Turin, via P. Giuria Turin, Italy
| | - Piermichele Kobauri
- Department of Drug Science and Technology, University of Turin, via P. Giuria Turin, Italy
| | - Zahid Ali
- Department of Biosciences, COMSATS Institute of Information Technology, Islamabad, Pakistan
| | - Francesca spyrakis
- Department of Drug Science and Technology, University of Turin, via P. Giuria Turin, Italy
| | - Pilar Cubas
- Department of Chemistry, University of Turin, via P. Giuria Turin, Italy
| | - Francesca Cardinale
- Department of Agricultural, Forestry and Food Science, Largo P. Braccini, Grugliasco (TO), Italy
| | - Cristina Prandi
- Centro Nacional de Biotecnología-CSIC, Plant Molecular Genetics Department, C/ Darwin, Campus UAM, Madrid, Spain
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