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…
The HD-ZIP class I transcription factor, HvHOX1 (Homeobox 1) or VRS1 (Vulgare Row-type Spike 1 or Six-rowed Spike 1), regulates lateral spikelet fertility in barley (Hordeum vulgare L.). It was shown that HvHOX1 has a high expression only in lateral spikelets, while its paralog HvHOX2 was found to be expressed in different plant organs. Yet, the mechanistic function of HvHOX1 and HvHOX2 during spikelet development is still fragmentary. Here, we show that compared to HvHOX1, HvHOX2 is more highly conserved across different barley genotypes and Hordeum species, hinting at a possibly vital but still unclarified biological role. Using bimolecular fluorescence complementation, DNA-binding, and transactivation assays, we validate that HvHOX1 and HvHOX2 are bona fide transcriptional activators that may potentially heterodimerize. Accordingly, both genes exhibit similar spatiotemporal expression patterns during spike development and growth, albeit their mRNA levels differ quantitatively. We show that HvHOX1 delays the lateral spikelet meristem differentiation and affects fertility by aborting the reproductive organs. Interestingly, the ancestral relationship of these genes inferred from their co-expressed gene networks suggested that HvHOX1 and HvHOX2 might play a similar role during barley spikelet development. However, CRISPR-derived mutants of HvHOX1 and HvHOX2 demonstrated the suppressive role of HvHOX1 on lateral spikelets, while the loss of HvHOX2 does not influence spikelet development. Collectively, our study shows that through the suppression of reproductive organs, lateral spikelet fertility is regulated by HvHOX1, whereas HvHOX2 is dispensable for spikelet development in barley.
Publikation
Müllers, Y.; Sadr, A. S.; Schenderlein, M.; Pallab, N.; D. Davari, M.; Glebe, U.; Reifarth, M.;Acrylate‐derived RAFT polymers for enzyme hyperactivation – boosting the α‐chymotrypsin enzyme activity using tailor‐made poly(2‐carboxyethyl)acrylate (PCEA)ChemCatChem16e202301685(2024)DOI: 10.1002/cctc.202301685
We study the hyperactivation of α‐chymotrypsin (α‐ChT) using the acrylate polymer poly(2‐carboxyethyl) acrylate (PCEA) in comparison to the commonly used poly(acrylic acid) (PAA). The polymers are added during the enzymatic cleavage reaction of the substrate N‐glutaryl‐L‐phenylalanine p‐nitroanilide (GPNA). Enzyme activity assays reveal a pronounced enzyme hyperactivation capacity of PCEA, which reaches up to 950% activity enhancement, and is significantly superior to PAA (revealing an activity enhancement of approx. 450%). In a combined experimental and computational study, we investigate α‐ChT/polymer interactions to elucidate the hyperactivation mechanism of the enzyme. Isothermal titration calorimetry reveals a pronounced complexation between the polymer and the enzyme. Docking simulations reveal that binding of polymers significantly improves the binding affinity of GPNA to α‐ChT. Notably, a higher binding affinity is found for the α‐ChT/PCEA compared to the α‐ChT/PAA complex. Further molecular dynamics (MD) simulations reveal changes in the size of the active site in the enzyme/polymer complexes, with PCEA inducing a more pronounced alteration compared to PAA, facilitating an easier access for the substrate to the active site of α‐ChT.
Publikation
Dippe, M.; Davari, M. D.; Weigel, B.; Heinke, R.; Vogt, T.; Wessjohann, L. A.;Altering the regiospecificity of a catechol
O‐methyltransferase through rational design: Vanilloid vs. isovanilloid motifs in the B‐ring of flavonoidsChemCatChem14e202200511(2022)DOI: 10.1002/cctc.202200511
Rational re-design of the substrate pocket of phenylpropanoid-flavonoid O-methyltransferase (PFOMT) from Mesembryanthe-mum crystallinum, an enzyme that selectively methylates the 3’-position (= meta-position) in catechol-moieties of flavonoids to guiacol-moieties, provided the basis for the generation of variants with opposite, i. e. 4’- (para-) regioselectivity and enhanced catalytic efficiency. A double variant (Y51R/N202W) identified through a newly developed colorimetric assay efficiently modified the para-position in flavanone and flavano-nol substrates, providing access to the sweetener molecule hesperetin and other rare plant flavonoids having an isovanil-loid motif.
Publikation
Mittersteiner, M.; Pereira, G. S.; Silva, Y.; Wessjohann, L. A.; Bonacorso, H. G.; Martins, M. A. P.; Zanatta, N.;Substituent-driven selective N-/O-alkylation of 4-(trihalomethyl)pyrimidin-2(1H)-ones using brominated enonesJ. Org. Chem.874590-4602(2022)DOI: 10.1021/acs.joc.1c02919
The selective N- or O-alkylation of 4-(trihalomethyl)-pyrimidin-2(1H)-ones, using 5-bromo enones/enaminones as alkylating agents, is reported. It was found that the selectivity toward the N-or O-regioisomer is driven by the substituent present at the 6-position of the pyrimidine ring, thus enabling the preparation of each isomer as the sole product, in 60−95% yields. Subsequent cyclocondensation of the enaminone moiety with nitrogen dinucleophiles led to pyrimidine−azole conjugates in 55−83% yields.