Kathrin Castiglione

Kathrin Castiglione
Friedrich-Alexander-University of Erlangen-Nürnberg | FAU · Department of Chemical and Bioengineering

Professor

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64
Publications
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921
Citations

Publications

Publications (64)
Preprint
Full-text available
In this paper, we propose novel Transmitter (Tx) models for Molecular Communication (MC) systems based on functionalized Nanoparticles (NPs). Current Tx models often rely on simplifying assumptions for the molecule release and replenishment mechanisms. In contrast, we propose a Tx model where the signaling molecule release is controlled by a switch...
Article
To elucidate the function of oxidative phosphorylation (OxPhos) during B cell differentiation, we employ CD23Cre-driven expression of the dominant-negative K320E mutant of the mitochondrial helicase Twinkle (DNT). DNT-expression depletes mitochondrial DNA during B cell maturation, reduces the abundance of respiratory chain protein subunits encoded...
Preprint
In conventional molecular communication (MC) systems, the signaling molecules used for information transmission are stored, released, and then replenished by a transmitter (TX). However, the replenishment of signaling molecules at the TX is challenging in practice. Furthermore, in most envisioned MC applications, e.g., in the medical field, it is n...
Article
Full-text available
Microalgae are possible sources of antiviral substances, e.g. against cyprinid herpesvirus 3 (CyHV-3). Although this virus leads to high mortalities in aquacultures, there is no treatment available yet. Hence, ethanolic extracts produced with accelerated solvent extraction from six microalgal species ( Arthrospira platensis , Chlamydomonas reinhard...
Preprint
In conventional molecular communication (MC) systems, the signaling molecules used for information transmission are stored, released, and then replenished by a transmitter (TX). However, the replenishment of signaling molecules at the TX is challenging in practice. Furthermore, in most envisioned MC applications, e.g., in the medical field, it is n...
Article
Full-text available
Deracemizations are clearly preferable to kinetic resolutions in the production of chiral molecules from racemates, as they allow up to 100% chemical and optical yield. Here we present a new process route for multienzymatic deracemizations that is relevant for reaction systems with incompatible reaction conditions of the biocatalysts. This often ap...
Article
Multienzymatic cascade reactions are a powerful strategy for straightforward and highly specific synthesis of complex materials, such as active substances in drugs. Cross-inhibitions and incompatible reaction steps, however, often limit enzymatic activity and thus the conversion. Such limitations occur, e.g., in the enzymatic synthesis of the biolo...
Article
Next to water quality deterioration, cyanobacteria blooms can affect turnover of aqueous carbon, including dissolved inorganic carbon (DIC), dissolved organic carbon (DOC), and particulate organic carbon (POC). We investigated interactions of these three phases and their stable isotopes in a freshwater pond with periodic cyanobacterial blooms over...
Article
Full-text available
Hollow vesicles made from a single or double layer of block-copolymer molecules, called polymersomes, represent an important technological platform for new developments in nano-medicine and nano-biotechnology. A central aspect in creating functional polymersomes is their combination with proteins, especially through encapsulation in the inner cavit...
Article
Full-text available
Cyanobacteria have the capacity to use photosynthesis to fuel their metabolism, which makes them highly promising production systems for the sustainable production of chemicals. Yet, their dependency on visible light limits the cell‐density, which is a challenge for the scale‐up. Here, we show with the example of a light‐dependent biotransformation...
Preprint
Full-text available
Microalgae often stand out for their high biodiversity as well as their associated large number of potent bioactives. Therefore, they are interesting candidates as possible sources of antiviral substances, e.g. against cyprinid herpesvirus 3 (CyHV-3). Although this virus leads to high mortalities in aquacultures, there is no treatment available yet...
Preprint
Full-text available
The function of mitochondrial respiration during B cell fate decisions and differentiation remains equivocal. This study reveals that selection for mitochondrial fitness occurs during B cell activation and is essential for subsequent plasma cell differentiation. By expressing a mutated mitochondrial helicase in transitional B cells, we depleted mit...
Article
Artificial vesicles made of block copolymers, so-called polymersomes, represent a versatile chassis for the creation of functionalized nanocompartments with a wide range of biotechnological applications. The specific application depends on the biomolecules – usually proteins – that are positioned in the interior, in the membrane or on the surface o...
Article
Full-text available
Most commonly small outer membrane proteins, possessing between 8 and 12 β-strands, are not involved in transport but fulfill diverse functions such as cell adhesion or binding of ligands. An intriguing exception are the 8-stranded β-barrel proteins of the OmpW family, which are implicated in the transport of small molecules. A representative examp...
Article
Full-text available
The protein AlkL is known to increase permeability of the outer membrane of bacteria for hydrophobic molecules, yet the mechanism of transport has not been determined. Differing crystal and NMR structures of homologous proteins resulted in a controversy regarding the degree of structure and the role of long extracellular loops. Here we solve this c...
Article
Full-text available
There is an increasing interest in biocatalysis to perform chemical reactions in biphasic systems, consisting of an aqueous phase and a water immiscible organic solvent or ionic liquid. In most cases, the hydrophobic phase is used as reservoir for poorly water‐soluble substrates or for in situ product removal. However, many enzymes are solvent‐sens...
Article
Synthetic molecular communication (MC) is a new communication engineering paradigm which is expected to enable revolutionary applications such as smart drug delivery and real-time health monitoring. The design and implementation of synthetic MC systems (MCSs) at nano-and microscale is very challenging. This is particularly true for synthetic MCSs e...
Article
Full-text available
(2R,5R)-dihydrocarvone is an industrially applied building block that can be synthesized by site-selective and stereo-selective C=C bond bio-reduction of (R)-carvone. Escherichia coli (E. coli) cells overexpressing an ene reductase from Nostoc sp. PCC7120 (NostocER1) in combination with a cosubstrate regeneration system proved to be very effective...
Article
The asymmetric reduction of alkenes is a widely used transformation in industry. Ene reductases (ERs) are (βα)8‐barrel folded enzymes capable of catalyzing this hydrogenation reaction. At the expense of nicotinamide coenzymes, ERs can reduce a wide range of electron‐deficient alkenes in an anti‐specific manner and with high regio‐ and stereoselecti...
Article
Full-text available
The utilization of light energy to power organic-chemical transformations is a fundamental strategy of the terrestrial energy cycle. Inspired by the elegance of natural photosynthesis, much interdisciplinary research effort has been devoted to the construction of simplified cell mimics based on artificial vesicles to provide a novel tool for biocat...
Article
Determination of the environment surrounding a protein is often key to understanding function, and can also be used to infer structural properties of the protein itself. Using proton‐detected solid‐state NMR, we show that reduced spin diffusion within the protein under conditions of fast magic‐angle spinning, high magnetic field, and sample deutera...
Article
Full-text available
Polymersomes are hollow, spherical vesicles that are surrounded by a polymer membrane. The applied polymer must be amphiphilic to promote self-assembly in aqueous solution. At the same time, the polymer composition is highly versatile, which leads to diverse properties in terms of chemical and mechanical stability, membrane permeability and the abi...
Article
Recently, the interest in polymersomes as nanoreactors for synthetic applications has increased due to interesting proof-of-concept studies, indicating a versatile use of polymeric vesicles to compartmentalize complex reaction cascades. However, the low permeability of polymeric membranes and the requirement for a controlled mass transport across t...
Article
Multi-catalytic cascade reactions bear a great potential to minimize downstream and purification steps, leading to a drastic reduction of the produced waste. The picture represents different catalytic systems that have been applied in compartmentalization approaches to control the microenvironment of catalysts in a defined way, thereby making the c...
Chapter
Die Enzymkinetik beschäftigt sich mit der Untersuchung der Geschwindigkeit enzymkatalysierter Reaktionen. Durch die quantitative Analyse des Effekts verschiedener chemischer und physikalischer Parameter, wie beispielsweise Substrat- und Produktkonzentration oder Temperatur, auf die Umsetzungsgeschwindigkeit, können wichtige Informationen bezüglich...
Chapter
Bei enzymatischen Produktionsprozessen geht es um biokatalytische Stoffumwandlungen, an denen sehr häufig nur ein einzelnes Enzym (Einschrittreaktion) oder eine überschaubare Kaskade mehrerer Enzyme beteiligt sind. Diese Stoffumwandlungen werden auch als Biotransformationen bezeichnet. Im Gegensatz dazu werden bei mikrobiellen Prozessen, die Gegens...
Article
Uniform polymersomes (polymer vesicles) made of poly(2-methyloxazoline)15-b-poly(dimethylsiloxane)68-b-poly(2-methyloxazoline)15 (PMOXA15–PDMS68–PMOXA15) can be formed in miniaturized-stirred tank reactors by the aid of a recently published process. In this study, the occurring self-assembly mechanism was elucidated by using transmission electron m...
Article
Multi-catalytic cascade reactions bear a great potential to minimize downstream and purification steps, leading to a drastic reduction of the produced waste. In many examples, the compatibility of chemo- and biocatalytic steps could be easily achieved. Problems associated to the incompatibility of the catalysts and their reactions, however, are ver...
Article
The increased membrane stability of polymersomes compared to their liposomal counterparts is one of their most important advantages. Due to this benefit, polymer vesicles are intended to be used not only as carrier-systems for drug delivery purposes but also as nanoreactors for biotechnological applications. Within this work, the stability of polym...
Article
Polymer vesicles, so-called polymersomes, can be applied as carrier-systems and universal reaction compartments, due to the possibility to encapsulate guest molecules. Compared to common lipid vesicles, polymersomes show an increased stability and decreased membrane permeability. Control of the mass transport across the membrane is necessary for an...
Article
Very fast magic-angle spinning (MAS>80 kHz) NMR spectroscopy combined with high field magnets has enabled the acquisition of proton-detected spectra in fully protonated solid samples with sufficient resolution and sensitivity. One of the primary challenges in structure determination of protein is to observe long-range 1H-1H proximities. We demonstr...
Article
Incompatibilities encountered in multienzyme syntheses often arise from inhibition or inactivation of individual enzymes by low-molecular-mass compounds. Polymersomes have the tremendous yet unproven potential to enhance the performance of cascade reactions by spatial separation of enzymes from the respective source of incompatibility. A main chall...
Article
The outer membrane of gram-negative bacteria constitutes an important hurdle for the transport of hydrophobic molecules into the cell. Mass flux is often facilitated by various outer membrane proteins. These proteins are of biotechnological importance because they could help to improve the performance of whole-cell biocatalysts or be incorporated i...
Article
Multi-step enzymatic syntheses often show very complex regulation mechanisms. Hence, extensive studies are necessary to identify the optimal mode of operation and suitable reaction conditions. Besides the application of mechanistic process models, the miniaturization and parallelization of laboratory equipment can accelerate bioprocess optimization...
Article
The chiral building block (2R,5R)-dihydrocarvone can be synthesized by asymmetric reduction of the C[double bond; length as m-dash]C bond of (R)-carvone using ene-reductases. However, whole-cell biotransformations are challenging due to the toxicity of the substrate, its low solubility in aqueous media and the formation of alcohols as by-products....
Article
Polymersomes have some fundamental advantages compared to their liposomal counterparts. Due to the increased stability of the polymeric membrane, polymersomes are intended to be reasonably applicable as carrier-systems and universal reaction compartments for diverse medical and biotechnological applications. Regardless of the application area, suit...
Article
Full-text available
Background Hollow vesicles formed from block copolymers, so-called polymersomes, have been extensively studied in the last decade for their various applications in drug delivery, in diagnostics and as nanoreactors. The immobilization of proteins on the polymersomes’ surface can aid in cell targeting, lead to functional biosensors or add an addition...
Article
Enzymatic cascade reactions, i.e. the combination of several enzyme reactions in one pot without isolation of intermediates, have great potential for the establishment of sustainable chemical processes. However, many cascade reactions suffer from cross-inhibitions and enzyme inactivation by components of the reaction system. This study focuses on t...
Article
Polymer vesicles, so-called polymersomes, gain more and more attention as potential carriers for medical and biotechnological applications. To put the production of these nanocompartments into action at an industrial scale, an efficient and scalable process has to be established. Moreover, being able to control the resulting particle size distribut...
Article
Full-text available
Background: Whole cell biocatalysts and isolated enzymes are considered as state of the art in biocatalytic preparations for industrial applications. Whole cells as biocatalysts are disadvantageous if substrate or products are toxic to the cells or undesired byproducts are formed due to the cellular metabolism. The use of isolated enzymes in compa...
Article
Full-text available
Industrial biotechnology relies on the availability of highly efficient enzymes and production strains for the development of economically viable processes. Recent advances in the field of genome editing will greatly speed up the implementation of desired metabolic pathways and their optimization, thereby facilitating fast and cost-effective produc...
Article
N-Acyl-d-glucosamine 2-epimerase (AGE) is an important enzyme for the biocatalytic synthesis of N-acetylneuraminic acid (Neu5Ac). Due to the wide range of biological applications of Neu5Ac and its derivatives, there has been great interest in its large-scale synthesis. Thus, suitable strategies for achieving high-level production of soluble AGE are...
Article
Ursodeoxycholic acid (UDCA) is a bile acid which is used as pharmaceutical for the treatment of several diseases, such as cholesterol gallstones, primary sclerosing cholangitis or primary biliary cirrhosis. A potential chemo-enzymatic synthesis route of UDCA comprises the two-step reduction of dehydrocholic acid (DHCA) to 12-keto-ursodeoxycholic ac...
Article
Herein we describe the kinetic characterization of a fusion protein from the 3-ketoacyl-[acyl-carrier-protein]-reductase (KR) from Synechococcus PCC 7942 and a mutant formate dehydrogenase from Mycobacterium vaccae N10 (MycFDH). Upon purification, a specific proteolytic cleavage of the MycFDH was observed. The cleavage site was elucidated, which is...
Article
N-Acetylneuraminic acid, an important component of glycoconjugates with various biological functions, can be produced from N-acetyl-d-glucosamine (GlcNAc) and pyruvate using a one-pot, two-enzyme system consisting of N-acyl-d-glucosamine 2-epimerase (AGE) and N-acetylneuraminate lyase (NAL). In this system, the epimerase catalyzes the conversion of...
Article
The growing importance of biocatalysis in the syntheses of enantiopure molecules results from the benefits of enzymes regarding selectivity and specificity of the reaction and ecological issues of the process. Ene-reductases (ER) from the old yellow enzyme family have received much attention in the last years. These flavo-enzymes catalyze the trans...
Article
Ursodeoxycholic acid (UDCA) is a bile acid of industrial interest as it is used as an agent for the treatment of primary sclerosing cholangitis and the medicamentous, non-surgical dissolution of gallstones. Currently, it is prepared industrially from cholic acid following a seven-step chemical procedure with an overall yield of <30%. In this study,...
Article
The increasing demand for enantiopure molecules in the pharmaceutical and fine-chemical industry requires the availability of well-characterized and efficient biocatalysts for asymmetric syntheses. Thereby, asymmetric reduction of alkenes represents one of the most employed reactions for the production of chiral molecules. Here, we present a novel...
Article
N-Acetylneuraminate lyase (NAL) from Escherichia coli K12 is an important enzyme for the production of N-acetylneuraminic acid (Neu5Ac), catalyzing the reversible aldol condensation between N-acetyl-d-mannosamine (ManNAc) and pyruvate. Despite the industrial importance of this enzyme, its kinetic mechanism has never been elucidated before. The init...
Article
Full-text available
Formate dehydrogenases (FDHs) are frequently used for the regeneration of cofactors in biotransformations employing NAD(P)H-dependent oxidoreductases. Major drawbacks of most native FDHs are their strong preference for NAD(+) and their low operational stability in the presence of reactive organic compounds such as α-haloketones. In this study, the...
Article
Mathematical models and simulations have become indispensable tools for the characterization and optimization of enzymatic processes. Nonetheless, industrially relevant enzymes are often poorly characterized with respect to enzyme kinetics. For the description of bisubstrate reactions catalysed by oxidoreductases in many cases Michaelis–Menten kine...
Article
The need for new and efficient biocatalysts for asymmetric synthesis is caused by the increasing demand for enantiopure chiral alcohols in the chemical and pharmaceutical industries. One approach to find new enzymes for technical applications is the screening of biodiversity. The identification of a novel oxidoreductase in the freshwater cyanobacte...
Article
NADPH-dependent oxidoreductases are useful catalysts for the production of chiral synthons. However, preparative applications of oxidoreductases require efficient methods for in situ regeneration of the expensive nicotinamide cofactors. An advantageous method for cofactor regeneration is the construction of bifunctional fusion proteins composed of...
Article
Whole resting cells of cyano- and thio-bacteria Synechococcus and Paracoccus spp. were shown to possess inverting alkylsulfatase activity for a broad spectrum of sec-alkylsulfate esters, which furnished either (R)- or (S)-sec-alcohols from the corresponding rac-sulfate esters in an enantiocomplementary fashion. Low enantioselectivities (E-values 1–...
Article
Chiral alcohols constitute important intermediates in the synthesis of optically active compounds. These building blocks can be easily obtained by biocatalytic reduction of prochiral ketones. The discovery of a novel oxidoreductase in cyanobacteria capable of enantioselective reduction of even multi-halogenated ketones offers an alternative route t...
Article
A new ketoreductase useful for asymmetric synthesis of chiral alcohols was identified in the cyanobacterium Synechococcus sp. strain PCC 7942. Mass spectrometry of trypsin-digested peptides identified the protein as 3-ketoacyl-[acyl-carrier-protein] reductase (KR) (EC 1.1.1.100). The gene, referred to as fabG, was cloned, functionally expressed in...
Article
Here, we report the identification of a new human leukocyte antigen (HLA)-B*44 allele found almost simultaneous in three DNA samples which were part of routine bone marrow donor typing by order of the German registry 'Aktion Knochenmarkspende Bayern'. The samples appeared noticeable in different polymerase chain reactions using sequence-specific pr...
Article
A new human leukocyte antigen (HLA)-B allele was found during routine typing of samples for a German unrelated bone marrow donor registry, the "Aktion Knochenmarkspende Bayern". After first interpretation of data of two independent low-resolution sequence-specific oligonucleotide typing tests, a B*51 variant was suggested. Further analysis via sequ...

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