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A flavin-dependent monooxygenase produces nitrogenous tomato aroma volatiles using cysteine as a nitrogen source. Proc Natl Acad Sci U S A 2022; 119:2118676119. [PMID: 35131946 PMCID: PMC8851548 DOI: 10.1073/pnas.2118676119] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/17/2021] [Indexed: 11/19/2022] Open
Abstract
Aroma is an important factor in consumer perception and acceptance of fresh tomatoes and involves a cocktail of several dozen compounds. Tomato fruits produce uncommon nitrogen-containing volatiles derived mainly from the amino acids leucine and phenylalanine. These volatiles have strong positive correlations with consumer liking. We show that an enzyme active in ripening tomatoes is responsible for the production of all nitrogenous volatiles in tomato fruit, at the expense of substrates derived from cysteine and volatile aldehydes. This discovery defines a cysteine-dependent route to nitrogenous volatiles in plants, prompting a reconsideration of the impact of sulfur metabolism on tomato flavor and quality. Tomato (Solanum lycopersicum) produces a wide range of volatile chemicals during fruit ripening, generating a distinct aroma and contributing to the overall flavor. Among these volatiles are several aromatic and aliphatic nitrogen-containing compounds for which the biosynthetic pathways are not known. While nitrogenous volatiles are abundant in tomato fruit, their content in fruits of the closely related species of the tomato clade is highly variable. For example, the green-fruited species Solanum pennellii are nearly devoid, while the red-fruited species S. lycopersicum and Solanum pimpinellifolium accumulate high amounts. Using an introgression population derived from S. pennellii, we identified a locus essential for the production of all the detectable nitrogenous volatiles in tomato fruit. Silencing of the underlying gene (SlTNH1;Solyc12g013690) in transgenic plants abolished production of aliphatic and aromatic nitrogenous volatiles in ripe fruit, and metabolomic analysis of these fruit revealed the accumulation of 2-isobutyl-tetrahydrothiazolidine-4-carboxylic acid, a known conjugate of cysteine and 3-methylbutanal. Biosynthetic incorporation of stable isotope-labeled precursors into 2-isobutylthiazole and 2-phenylacetonitrile confirmed that cysteine provides the nitrogen atom for all nitrogenous volatiles in tomato fruit. Nicotiana benthamiana plants expressing SlTNH1 readily transformed synthetic 2-substituted tetrahydrothiazolidine-4-carboxylic acid substrates into a mixture of the corresponding 2-substituted oxime, nitro, and nitrile volatiles. Distinct from other known flavin-dependent monooxygenase enzymes in plants, this tetrahydrothiazolidine-4-carboxylic acid N-hydroxylase catalyzes sequential hydroxylations. Elucidation of this pathway is a major step forward in understanding and ultimately improving tomato flavor quality.
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Espeland LO, Georgiou C, Klein R, Bhukya H, Haug BE, Underhaug J, Mainkar PS, Brenk R. An Experimental Toolbox for Structure-Based Hit Discovery for P. aeruginosa FabF, a Promising Target for Antibiotics. ChemMedChem 2021; 16:2715-2726. [PMID: 34189850 PMCID: PMC8518799 DOI: 10.1002/cmdc.202100302] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 06/22/2021] [Indexed: 12/12/2022]
Abstract
FabF (3-oxoacyl-[acyl-carrier-protein] synthase 2), which catalyses the rate limiting condensation reaction in the fatty acid synthesis II pathway, is an attractive target for new antibiotics. Here, we focus on FabF from P. aeruginosa (PaFabF) as antibiotics against this pathogen are urgently needed. To facilitate exploration of this target we have set up an experimental toolbox consisting of binding assays using bio-layer interferometry (BLI) as well as saturation transfer difference (STD) and WaterLOGSY NMR in addition to robust conditions for structure determination. The suitability of the toolbox to support structure-based design of FabF inhibitors was demonstrated through the validation of hits obtained from virtual screening. Screening a library of almost 5 million compounds resulted in 6 compounds for which binding into the malonyl-binding site of FabF was shown. For one of the hits, the crystal structure in complex with PaFabF was determined. Based on the obtained binding mode, analogues were designed and synthesised, but affinity could not be improved. This work has laid the foundation for structure-based exploration of PaFabF.
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Affiliation(s)
- Ludvik Olai Espeland
- Department of BiomedicineUniversity of BergenJonas Lies Vei 915020BergenNorway
- Department of ChemistryUniversity of BergenAllégaten 415007BergenNorway
| | - Charis Georgiou
- Department of BiomedicineUniversity of BergenJonas Lies Vei 915020BergenNorway
| | - Raphael Klein
- Department of BiomedicineUniversity of BergenJonas Lies Vei 915020BergenNorway
- Institute of Pharmacy and BiochemistryJohannes Gutenberg UniversityStaudingerweg 555128MainzGermany
| | - Hemalatha Bhukya
- Department of Organic Synthesis & Process ChemistryCSIR-Indian Institute of Chemical TechnologyTarnakaHyderabad500007India
| | - Bengt Erik Haug
- Department of ChemistryUniversity of BergenAllégaten 415007BergenNorway
| | - Jarl Underhaug
- Department of ChemistryUniversity of BergenAllégaten 415007BergenNorway
| | - Prathama S. Mainkar
- Department of Organic Synthesis & Process ChemistryCSIR-Indian Institute of Chemical TechnologyTarnakaHyderabad500007India
| | - Ruth Brenk
- Department of BiomedicineUniversity of BergenJonas Lies Vei 915020BergenNorway
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Bustillo Trueba P, Jaskula-Goiris B, Ditrych M, Filipowska W, De Brabanter J, De Rouck G, Aerts G, De Cooman L, De Clippeleer J. Monitoring the evolution of free and cysteinylated aldehydes from malt to fresh and forced aged beer. Food Res Int 2021; 140:110049. [PMID: 33648274 DOI: 10.1016/j.foodres.2020.110049] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 12/14/2020] [Accepted: 12/16/2020] [Indexed: 10/22/2022]
Abstract
During storage, beer staling coincides with a gradual increase in the concentrations of aldehydes resulting in the appearance of undesirable flavours. Cysteinylated aldehydes, also referred to as 2-substituted 1,3-thiazolidine-4-carboxylic acids, have been proposed as potential precursors of this increase. This study aimed to further understand the origin of aldehydes in aged beer, by monitoring both free and cysteinylated aldehydes throughout the brewing process, from the raw materials until the stored product. Quantification of free and cysteinylated aldehydes was performed for two different brews via headspace solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) and ultra-high performance liquid chromatography-mass spectrometry (UHPLC-MS), respectively. All selected marker aldehydes were quantified in malt, wort, and the resulting fresh and aged beer samples. Cysteinylated aldehydes were quantifiable in malt and up to the wort boiling phase. The highest levels of free aldehydes were found in malt, whereas cysteinylated aldehydes showed highest levels at mashing-in pointing to their formation during both malting and subsequent mashing-in. During beer ageing, an increase in all free aldehydes was measured. In particular, a rise in 2-methylpropanal and furfural is most striking. Although the presented experimental data obtained on malt and brewery samples do support the concept of bound-state aldehydes, cysteinylated aldehydes cannot be consider as the cause of increasing levels of staling aldehydes during beer ageing.
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Affiliation(s)
- P Bustillo Trueba
- KU Leuven, Department of Microbial and Molecular Systems (M(2)S), Cluster for Bioengineering Technology (CBeT), Laboratory of Enzyme, Fermentation and Brewing Technology (EFBT), Technology Campus Ghent, Gebroeders De Smetstraat 1, B-9000 Ghent, Belgium.
| | - B Jaskula-Goiris
- KU Leuven, Department of Microbial and Molecular Systems (M(2)S), Cluster for Bioengineering Technology (CBeT), Laboratory of Enzyme, Fermentation and Brewing Technology (EFBT), Technology Campus Ghent, Gebroeders De Smetstraat 1, B-9000 Ghent, Belgium.
| | - M Ditrych
- KU Leuven, Department of Microbial and Molecular Systems (M(2)S), Cluster for Bioengineering Technology (CBeT), Laboratory of Enzyme, Fermentation and Brewing Technology (EFBT), Technology Campus Ghent, Gebroeders De Smetstraat 1, B-9000 Ghent, Belgium.
| | - W Filipowska
- KU Leuven, Department of Microbial and Molecular Systems (M(2)S), Cluster for Bioengineering Technology (CBeT), Laboratory of Enzyme, Fermentation and Brewing Technology (EFBT), Technology Campus Ghent, Gebroeders De Smetstraat 1, B-9000 Ghent, Belgium.
| | - J De Brabanter
- KU Leuven, Department of Microbial and Molecular Systems (M(2)S), Cluster for Bioengineering Technology (CBeT), Laboratory of Enzyme, Fermentation and Brewing Technology (EFBT), Technology Campus Ghent, Gebroeders De Smetstraat 1, B-9000 Ghent, Belgium.
| | - G De Rouck
- KU Leuven, Department of Microbial and Molecular Systems (M(2)S), Cluster for Bioengineering Technology (CBeT), Laboratory of Enzyme, Fermentation and Brewing Technology (EFBT), Technology Campus Ghent, Gebroeders De Smetstraat 1, B-9000 Ghent, Belgium.
| | - G Aerts
- KU Leuven, Department of Microbial and Molecular Systems (M(2)S), Cluster for Bioengineering Technology (CBeT), Laboratory of Enzyme, Fermentation and Brewing Technology (EFBT), Technology Campus Ghent, Gebroeders De Smetstraat 1, B-9000 Ghent, Belgium.
| | - L De Cooman
- KU Leuven, Department of Microbial and Molecular Systems (M(2)S), Cluster for Bioengineering Technology (CBeT), Laboratory of Enzyme, Fermentation and Brewing Technology (EFBT), Technology Campus Ghent, Gebroeders De Smetstraat 1, B-9000 Ghent, Belgium.
| | - J De Clippeleer
- Innovation centre for Brewing & Fermentation - IBF, Ghent University, Faculty of Bioscience Engineering, Department of Biotechnology, Valentin Vaerwyckweg 1, B-9000 Ghent, Belgium; Innovation centre for Brewing & Fermentation - IBF, HOGENT University of Applied Sciences and Arts, Department of Life Sciences and Industrial Technology, Research Centre AgroFoodNature, Valentin Vaerwyckweg 1, B-9000 Ghent, Belgium.
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Jin Q, Wang F, Chen S, Zhou L, Jiang H, Zhang L, Liu M. Circularly Polarized Luminescence of Aluminum Complexes for Chiral Sensing of Amino Acid and Amino Alcohol. Chem Asian J 2019; 15:319-324. [PMID: 31825169 DOI: 10.1002/asia.201901480] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 12/06/2019] [Indexed: 11/06/2022]
Abstract
Determination of the absolute configuration (AC) of chiral molecules is a key issue in many fields related to chirality such as drug development, the asymmetric reaction screening, and the structure determination of natural compounds. Although various methods, such as X-ray crystallography and NMR spectroscopy, are used to determine the AC, a simple and cheap alternative method is always anticipated. So far, electronic circular dichroism (ECD) spectroscopy has been widely used to ascertain the AC and enantiomeric excess (ee) values by applying appropriate organic probes. Here, circularly polarized luminescence (CPL) spectroscopy was applied to determine the AC and ee values of a series of amino acid and amino alcohol. The measurements were conducted by mixing the amino acids or amino alcohols with an achiral 1-hydroxy-2-naphthaldehyde. Upon in situ formation of the Schiff base complexes, the system showed emission enhancement and CPL in the presence of Al3+ , whose intensity and sign can be used to assign the chiral sense of the amino acids and amino alcohols. The authenticity of the method was further compared with the established CD spectroscopy, revealing that CPL spectra of formed Al3+ complex were effective to determine the AC of chiral species.
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Affiliation(s)
- Qingxian Jin
- Henan Provincial Key Laboratory of Surface and Interface Science, Zhengzhou University of Light Industry, Zhengzhou, Henan, 450002, P. R. China
| | - Fulin Wang
- Henan Provincial Key Laboratory of Surface and Interface Science, Zhengzhou University of Light Industry, Zhengzhou, Henan, 450002, P. R. China.,Beijing National Laboratory for Molecular Science, CAS Key Laboratory of Colloid Interface and Chemical Thermodynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Shuyu Chen
- Henan Provincial Key Laboratory of Surface and Interface Science, Zhengzhou University of Light Industry, Zhengzhou, Henan, 450002, P. R. China
| | - Liming Zhou
- Henan Provincial Key Laboratory of Surface and Interface Science, Zhengzhou University of Light Industry, Zhengzhou, Henan, 450002, P. R. China
| | - Hejin Jiang
- Beijing National Laboratory for Molecular Science, CAS Key Laboratory of Colloid Interface and Chemical Thermodynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Li Zhang
- Beijing National Laboratory for Molecular Science, CAS Key Laboratory of Colloid Interface and Chemical Thermodynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Minghua Liu
- Beijing National Laboratory for Molecular Science, CAS Key Laboratory of Colloid Interface and Chemical Thermodynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China
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Bustillo Trueba P, Jaskula-Goiris B, De Clippeleer J, Goiris K, Praet T, Sharma U, Van der Eycken E, Sanders M, Vincken JP, De Brabanter J, De Rouck G, Aerts G, De Cooman L. Validation of an ultra-high-performance liquid chromatography-mass spectrometry method for the quantification of cysteinylated aldehydes and application to malt and beer samples. J Chromatogr A 2019; 1604:460467. [DOI: 10.1016/j.chroma.2019.460467] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2019] [Revised: 08/14/2019] [Accepted: 08/19/2019] [Indexed: 10/26/2022]
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Ershov АY, Lagoda IV, Nasledov DG, Vasil’eva MY, Kuleshova LY, Pavlova LV, Yakimanskii AV. Synthesis of (2R,4R)-2-alkyl-3-(2-mercaptobenzoyl)thiazolidine-4-carboxylic acids. RUSSIAN JOURNAL OF ORGANIC CHEMISTRY 2017. [DOI: 10.1134/s1070428017110124] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Jagtap RM, Rizvi MA, Dangat YB, Pardeshi SK. Crystal structure, computational studies, and stereoselectivity in the synthesis of 2-aryl-thiazolidine-4-carboxylic acids via in situ imine intermediate. J Sulphur Chem 2016. [DOI: 10.1080/17415993.2016.1156116] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Rohidas M. Jagtap
- Department of Chemistry, Savitribai Phule Pune University (formerly University of Pune), Pune, India
| | - Masood A. Rizvi
- Department of Chemistry, University of Kashmir, Srinagar, India
| | - Yuvraj B. Dangat
- Physical Chemistry Division, CSIR-National Chemical Laboratory, Pune, India
| | - Satish K. Pardeshi
- Department of Chemistry, Savitribai Phule Pune University (formerly University of Pune), Pune, India
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