Geschmack ist vorhersagbar: Mit FlavorMiner. FlavorMiner heißt das Tool, das IPB-Chemiker und Partner aus Kolumbien jüngst entwickelt haben. Das Programm kann, basierend auf maschinellem Lernen (KI), anhand der…
Seit Februar 2021 bietet Wolfgang Brandt, ehemaliger Leiter der Arbeitsgruppe Computerchemie am IPB, sein Citizen Science-Projekt zur Pilzbestimmung an. Dafür hat er in regelmäßigen Abständen öffentliche Vorträge zur Vielfalt…
Hashemi Haeri, H.; Schneegans, N.; Eisenschmidt-Bönn, D.; Brandt, W.; Wittstock, U.; Hinderberger, D.;Characterization of the active site in the thiocyanate-forming protein from Thlaspi arvense (TaTFP) using EPR spectroscopyBiol. Chem.405105-118(2024)DOI: 10.1515/hsz-2023-0187
Glucosinolates are plant thioglucosides, which act as chemical defenses. Upon tissue damage, their myrosinase-catalyzed hydrolysis yields aglucones that rearrange to toxic isothiocyanates. Specifier proteins such as thiocyanate-forming protein from Thlaspi arvense (TaTFP) are non-heme iron proteins, which capture the aglucone to form alternative products, e.g. nitriles or thiocyanates. To resolve the electronic state of the bound iron cofactor in TaTFP, we applied continuous wave electron paramagnetic resonance (CW EPR) spectroscopy at X-and Q-band frequencies (∼9.4 and ∼34 GHz). We found characteristic features of high spin and low spin states of a d5 electronic configuration and local rhombic symmetry during catalysis. We monitored the oxidation states of bound iron during conversion of allylglucosinolate by myrosinase and TaTFP in presence and absence of supplemented Fe2+. Without added Fe2+, most high spin features of bound Fe3+ were preserved, while different g’-values of the low spin part indicated slight rearrangements in the coordination sphere and/or structural geometry. We also examined involvement of the redox pair Fe3+/Fe2 in samples with supplemented Fe2+. The absence of any EPR signal related to Fe3+ or Fe2+ using an iron-binding deficient TaTFP variant allowed us to conclude that recorded EPR signals originated from the bound iron cofactor.
Publikation
Cankar, K.; Hakkert, J. C.; Sevenier, R.; Papastolopoulou, C.; Schipper, B.; Baixinho, J. P.; Fernández, N.; Matos, M. S.; Serra, A. T.; Santos, C. N.; Vahabi, K.; Tissier, A.; Bundock, P.; Bosch, D.;Lactucin synthase inactivation boosts the accumulation of anti-inflammatory 8-deoxylactucin and its derivatives in Chicory (Cichorium intybus L.)J. Agr. Food Chem.716061-6072(2023)DOI: 10.1021/acs.jafc.2c08959
For several sesquiterpene lactones (STLs) found in Asteraceae plants, very interesting biomedical activities have been demonstrated. Chicory roots accumulate the guaianolide STLs 8-deoxylactucin, lactucin, and lactucopicrin predominantly in oxalated forms in the latex. In this work, a supercritical fluid extract fraction of chicory STLs containing 8-deoxylactucin and 11β,13-dihydro-8-deoxylactucin was shown to have anti-inflammatory activity in an inflamed intestinal mucosa model. To increase the accumulation of these two compounds in chicory taproots, the lactucin synthase that takes 8-deoxylactucin as the substrate for the regiospecific hydroxylation to generate lactucin needs to be inactivated. Three candidate cytochrome P450 enzymes of the CYP71 clan were identified in chicory. Their targeted inactivation using the CRISPR/Cas9 approach identified CYP71DD33 to have lactucin synthase activity. The analysis of the terpene profile of the taproots of plants with edits in CYP71DD33 revealed a nearly complete elimination of the endogenous chicory STLs lactucin and lactucopicrin and their corresponding oxalates. Indeed, in the same lines, the interruption of biosynthesis resulted in a strong increase of 8-deoxylactucin and its derivatives. The enzyme activity of CYP71DD33 to convert 8-deoxylactucin to lactucin was additionally demonstrated in vitro using yeast microsome assays. The identified chicory lactucin synthase gene is predominantly expressed in the chicory latex, indicating that the late steps in the STL biosynthesis take place in the latex. This study contributes to further elucidation of the STL pathway in chicory and shows that root chicory can be positioned as a crop from which different health products can be extracted.
Publikation
Gorzolka, K.; Perino, E. H. B.; Lederer, S.; Smolka, U.; Rosahl, S.;Lysophosphatidylcholine 17:1 from the Leaf Surface of the Wild Potato Species Solanum bulbocastanum Inhibits Phytophthora infestansJ. Agr. Food Chem.695607-5617(2021)DOI: 10.1021/acs.jafc.0c07199
Late blight, caused by the oomycete Phytophthora infestans, is economically the most important foliar disease of potato. To assess the importance of the leaf surface, as the site of the first encounter of pathogen and host, we performed untargeted profiling by liquid chromatography–mass spectrometry of leaf surface metabolites of the susceptible cultivated potato Solanum tuberosum and the resistant wild potato species Solanum bulbocastanum. Hydroxycinnamic acid amides, typical phytoalexins of potato, were abundant on the surface of S. tuberosum, but not on S. bulbocastanum. One of the metabolites accumulating on the surface of the wild potato was identified as lysophosphatidylcholine carrying heptadecenoic acid, LPC17:1. In vitro assays revealed that both spore germination and mycelial growth of P. infestans were efficiently inhibited by LPC17:1, suggesting that leaf surface metabolites from wild potato species could contribute to early defense responses against P. infestans.
Publikation
Fayek, N. M.; Mekky, R. H.; Dias, C. N.; Kropf, M.; Heiss, A. G.; Wessjohann, L. A.; Farag, M. A.;UPLC-MS Metabolome-Based Seed Classification of 16 Vicia Species: A Prospect for Phyto-Equivalency and Chemotaxonomy of Different AccessionsJ. Agr. Food Chem.695252-5266(2021)DOI: 10.1021/acs.jafc.0c06054
Seeds of domesticated Vicia (vetch) species (family Fabaceae-Faboideae)
are produced and consumed worldwide for their nutritional value. Seed
accessions belonging to 16 different species of Vicia—both domesticated
and wild taxa—were subjected to a chemotaxonomic study using
ultraperformance liquid chromatography–mass spectrometry (UPLC-MS)
analyzed by chemometrics. A total of 89 metabolites were observed in the
examined Vicia accessions. Seventy-eight out of the 89 detected
metabolites were annotated. Metabolites quantified belonged to several
classes, viz., flavonoids, procyanidins, prodelphinidins, anthocyanins,
stilbenes, dihydrochalcones, phenolic acids, coumarins, alkaloids,
jasmonates, fatty acids, terpenoids, and cyanogenics, with flavonoids
and fatty acids amounting to the major classes. Flavonoids, fatty acids,
and anthocyanins showed up as potential chemotaxonomic markers in Vicia
species discrimination. Fatty acids were more enriched in Vicia faba specimens, while the abundance of flavonoids was the highest in Vicia parviflora. Anthocyanins allowed for discrimination between Vicia hirsuta and Vicia sepium.
To the best of our knowledge, this is the first report on employing
UPLC-MS metabolomics to discern the diversity of metabolites at the
intrageneric level among Vicia species.