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Item type:Publication, Access status: with files , The pH-Dependence of the Hydration of 5-Formylcytosine: an Experimental and Theoretical Study5-Formylcytosine is an important nucleobase in epigenetic regulation, whose hydrate form has been implicated in the formation of 5-carboxycytosine as well as oligonucleotide binding events. The hydrate content of 5-formylcytosine and its uracil derivative has now been quantified using a combination of NMR and mass spectroscopic measurements as well as theoretical studies. Small amounts of hydrate can be identified for the protonated form of 5-formylcytosine and for neutral 5-formyluracil. For neutral 5-formylcytosine, however, direct detection of the hydrate was not possible due to its very low abundance. This is in full agreement with theoretical estimates.Publicationtype: Journal Article7 38 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Modeling alcohol dehydrogenase catalysis in deep eutectic solvent/water mixtures(Wiley-VCH, 2020-03-16); ; ; ; The use of oxidoreductases (EC1) in non-conventional reaction media has been increasingly explored. In particular, deep eutectic solvents (DESs) have emerged as a novel class of solvents. Herein, an in-depth study of bioreduction with an alcohol dehydrogenase (ADH) in the DES glyceline is presented. The activity and stability of ADH in mixtures of glyceline/water with varying water contents were measured. Furthermore, the thermodynamic water activity and viscosity of mixtures of glyceline/water have been determined. For a better understanding of the observations, molecular dynamics simulations were performed to quantify the molecular flexibility, hydration layer, and intraprotein hydrogen bonds of ADH. The behavior of the enzyme in DESs follows the classic dependence of water activity (aW) in non-conventional media. At low aW values (<0.2), ADH does not show any activity; at higher aW values, the activity was still lower than that in pure water due to the high viscosities of the DES. These findings could be further explained by increased enzyme flexibility with increasing water content.Publicationtype: Journal ArticleScopus© Citations 28 235 219 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Convergent Cascade Catalyzed by Monooxygenase–Alcohol Dehydrogenase Fusion Applied in Organic Media(2019-07-01); ; ; ; With the aim of applying redox-neutral cascade reactions in organic media, fusions of a type II flavin-containing monooxygenase (FMO-E) and horse liver alcohol dehydrogenase (HLADH) were designed. The enzyme orientation and expression vector were found to influence the overall fusion enzyme activity. The resulting bifunctional enzyme retained the catalytic properties of both individual enzymes. The lyophilized cell-free extract containing the bifunctional enzyme was applied for the convergent cascade reaction consisting of cyclobutanone and butane-1,4-diol in different microaqueous media with only 5 % (v/v) aqueous buffer without any addition of external cofactor. Methyl tert-butyl ether and cyclopentyl methyl ether were found to be the best organic media for the synthesis of γ-butyrolactone, resulting in about 27 % analytical yield.Publicationtype: Journal Article127 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Evaluation of the Substrate Scope of Benzoic Acid (De)carboxylases According to Chemical and Biochemical Parameters(2016-10-04); ; The enzymatic carboxylation of phenolic compounds has been attracting increasing interest in recent years, owing to its regioselectivity and technical potential as a biocatalytic equivalent for the Kolbe–Schmitt reaction. Mechanistically the reaction was demonstrated to occur through electrophilic aromatic substitution/water elimination with bicarbonate as a cosubstrate. The effects of the substituents on the phenolic ring have not yet been elucidated in detail, but this would give detailed insight into the substrate–activity relationship and would provide predictability for the acceptance of future substrates. In this report we show how the kinetic and (apparent) thermodynamic behavior can be explained through the evaluation of linear free energy relationships based on electronic, steric, and geometric parameters and through the consideration of enzyme–ligand interactions. Moreover, the similarity between the benzoic acid decarboxylases and the amidohydrolases superfamily is investigated, and promiscuous hydrolytic activity of the decarboxylase in the context of the hydrolysis of an activated ester bond has been established.Publicationtype: Journal Article62 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , 101 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Parallel incorporation of different fluorinated amino acids : on the way to "teflon" proteins(Chemical Equation Presented) Nonstick proteins? We report the successful residue-specific fluorination of 24 positions in a lipase by simultaneous incorporation of three different noncanonical amino acids. The enzyme produced in a polyauxotrophic E. coli strain structurally tolerates all fluorine atoms and retains its catalytic activity very well. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA.Publicationtype: Journal Article130