FG Physikalische Chemie / Biophysikalische Chemie

31 Items

Recent Submissions
Competition of Pyridoxal 5'-Phosphate with Ribulose 1,5-Bisphosphate and Effector Sugar Phosphates at the Reaction Centers of the Spinach Ribulose 1,5-Bisphosphate Carboxylase/Oxygenase

Vater, Joachim ; Gaudszun, Thomas ; Scharnow, Harald ; Salnikow, Johann (1980)

The Stimulation of the carboxylase reaction by effectors of ribulose 1,5-bisphosphate carboxyl­ ase/oxygenase displays higher sensitivity towards pyridoxal 5'-phosphate inhibition than the catalytical process itself. Pyridoxal 5'-phosphate binding to the enzyme is not affected by the modulators 6-phospho-gluconate and fructose 1,6-bisphosphate at low concentrations at which these agents stimula...

Oxygen-Evolving Extracts from a Thermophilic Cyanobacterium Synechococcus sp.

Miyairi, Sachio ; Schatz, Günther H. (1983)

Spheroplast membranes of a thermophilic cyanobacterium Synechococcus sp. have been treated with the detergent lauryldim ethylam ine oxide (LDAO). The resulting extracts show (1) light-induced O2 evolution with artificial electron acceptors, (2) four-fold enhancement of the O2 evolution relative to chlorophyll, (3) parallel increase of both the molar ratios of PS 2/C hl and cyt b559/Chl in the e...

Studies on the Functional Mechanism of System II Herbicides in Isolated Chloroplasts

Renger, Gernot ; Hagemann, A. ; Vermaas, Wim F.J. (1984)

The effect of specific proteolytic enzymes on variable fluorescence, p-benzoquinone-mediated oxygen evolution, PS II herbicide (atrazine and bromoxynil) binding, and protein degradation has been analyzed in isolated class II pea chloroplasts. It was found that: 1. Trypsin and a lysine-specific protease effectively reduce the maximum chlorophyll-a fluorescence yield, whereas the initial fluoresc...

Herbicide/Quinone Binding Interactions in Photosystem II

Vermaas, Wim F.J. ; Renger, Gernot ; Arntzen, Charles J. (1984)

Many inhibitors prevent the oxidation of the primary electron-accepting quinone (QA) by the secondary quinone (Qв) in photosystem II by displacement of Qв from its binding site. On the other hand, plastoquinone-1 and 6-azido-5-decyl-2,3-dim ethoxy-p-benzoquinone displace herbicides. Binding studies show the herbicide/quinone interaction to be (apparently) competitive.The herbicide binding is in...

Structure of the ATP-Synthase from Chloroplasts and Mitochondria Studied by Electron Microscopy

Boekema, Egbert J. ; Schmidt, Günter ; Gräber, Peter ; Berden, Jan A. (1988)

The structure of the ATP-synthase, F0F1 , from spinach chloroplasts and beef heart mitochondria has been investigated by electron microscopy with negatively stained specimens. The detergent-solubilized ATP-synthase forms string-like structures in which the F0 parts are aggregated. In most cases, the F, parts are arranged at alternating sides along the string. The F0 part has an approximate cyli...

Funktion, Modifikation und Anwendung von O2-toleranten, NAD(P)+-reduzierenden [NiFe]-Hydrogenasen

Preissler, Janina (2018)

Lösliche, NAD(P)+-abhängige [NiFe]-Hydrogenasen („Soluble Hydrogenase“, SH) katalysieren die reversible Spaltung von H2 in jeweils zwei Elektronen und Protonen sowie die damit gekoppelte Reduktion des Pyridinnukleotid-Kofaktors. Die beiden Reaktionen erfolgen in zwei unterschiedlichen Modulen, dem Hydrogenasemodul HoxHY, das das H2-spaltende aktive [NiFe]-Zentrum trägt, und dem flavinhaltigen N...

Activation of H2 and CO2

Wahlefeld, Stefan Malte (2018)

The activation of small molecules, such as hydrogen or carbon dioxide, is an important part in a renewable, green chemistry in the future in our society. In this context, nature already shaped metalloenzymes, which are capable of catalyzing a wide variety of reactions. In order to exploit their biotechnological potential and provide an optimum performance, a fundamental understanding of their c...

Investigation of membrane-active peptides and proteins by vibrational spectroscopy

Forbrig, Enrico (2018)

The plasma membrane acts as the barrier and interface between the intracellular compartment and the extracellular environment. There are a variety of physical and chemical stimuli that are transmitted over the plasma membrane by means of integrated biomolecules, e.g. membrane proteins and peptides. To elucidate such processes in more detail, the development of artificial biomimetic membrane sys...

Computational chemistry studies on metallo-enzymes for the splitting of hydrogen and the interconversion between carbon monoxide and carbon dioxide

Tombolelli, Daria (2018)

Carbon monoxide dehydrogenases (CODH) are metallo-enzymes which perform the interconversion between CO and CO2. In particular, in the present work, nickel iron containing CODH from Carboxydothermus hydrogenoformans, is studied. Its catalytic mechanism is still unclear, because of the difficulties at the experimental level to trap substrate-bound intermediates and pure redox states. For this rea...

Spectroelectrochemical study of biomolecules in artificial membrane systems

Gonzalez, Barbara Daiana (2018)

This work presents a spectroeletrochemical approach combining electrochemical impedance spectroscopy (EIS) and surface-enhanced infrared absorption (SEIRA) spectroscopy to characterise the interaction of proteins and peptides with model membranes. The artificial membrane systems are assembled on a nanostructured Au-film, which is deposited on an attenuated total reflectance (ATR) crystal as a p...

Chemometrische Analysestrategien für Raman-spektroskopische Daten

Keidel, Anke (2018)

Gegenstand dieser Arbeit sind chemometrische Methoden zur Analyse komplexer Datensätze, die mittels Raman-Spektroskopie erzeugt werden. Anhand exemplarischer Problemstellungen werden geeignete Strategien zur Dechiffrierung der chemischen und physikalischen Informationen eines biologischen oder chemischen Systems aus experimentellen Spektren dargestellt und bewertet. Gemeinsames Ziel der verwend...

Elucidating the mechanism of action of antimicrobial peptides by means of computational approaches

Miguel Catalina, Alejandra de (2017)

Microorganism such as bacteria, viruses, fungi and some parasites, possess the inherent ability to cease the activity of an antimicrobial -for instance antibiotics, antivirals and antimalarials- against it. This property is known as antimicrobial resistance (AMR) and causes with time the ineffectiveness of standard treatments, helping infections persist and spread to other hosts. AMR is one of ...

Nuclear resonance vibrational spectroscopy reveals the FeS cluster composition and active site vibrational properties of an O-2-tolerant NAD(+)-reducing [NiFe] hydrogenase

Lauterbach, Lars ; Wang, Hongxin ; Horch, Marius ; Gee, Leland B. ; Yoda, Yoshitaka ; Tanaka, Yoshihito ; Zebger, Ingo ; Lenz, Oliver ; Cramer, Stephen P. (2015)

Hydrogenases are complex metalloenzymes that catalyze the reversible splitting of molecular hydrogen into protons and electrons essentially without overpotential. The NAD(+)-reducing soluble hydrogenase (SH) from Ralstonia eutropha is capable of H-2 conversion even in the presence of usually toxic dioxygen. The molecular details of the underlying reactions are largely unknown, mainly because of...

Surface enhanced vibrational spectroscopic evidence for an alternative DNA-independent redox activation of endonuclease III

Moe, Elin ; Sezer, Murat ; Hildebrandt, Peter ; Todorovic, Smilja (2015)

Surface enhanced vibrational spectro-electrochemistry of endonuclease III provides direct evidence that the [4Fe-4S] cluster is responsible for the enzyme redox activity, and that this process is not exclusively DNA-mediated, as currently proposed. We report the first surface enhanced resonance Raman spectrum of a [4Fe-4S](2+) cluster containing enzyme.

Microporous polymer network films covalently bound to gold electrodes

Becker, Daniel ; Heidary, Nina ; Horch, Marius ; Gernert, Ulrich ; Zebger, Ingo ; Schmidt, Johannes ; Fischer, Anna ; Thomas, Arne (2015)

Covalent attachment of a microporous polymer network (MPN) on a gold surface is presented. A functional bromophenyl-based self-assembled monolayer (SAM) formed on the gold surface acts as co-monomer in the polymerisation of the MPN yielding homogeneous and robust coatings. Covalent binding of the films to the electrode is confirmed by SEIRAS measurements.

The influence of poly(ethylene glycol) on the micelle formation of alkyl maltosides used in membrane protein crystallization

Müh, Frank ; DiFiore, Dörte ; Zouni, Athina (2015)

With the aim of better understanding the phase behavior of alkyl maltosides (n-alkyl-beta-D-maltosides, C(n)G(2)) under the conditions of membrane protein crystallization, we studied the influence of poly(ethylene glycol) (PEG) 2000, a commonly used precipitating agent, on the critical micelle concentration (CMC) of the alkyl maltosides by systematic variation of the number n of carbon atoms in...

Cofactor composition and function of a H2-sensing regulatory hydrogenase as revealed by Mossbauer and EPR spectroscopy

Roncaroli, Federico ; Bill, Eckhard ; Friedrich, Bärbel ; Lenz, Oliver ; Lubitz, Wolfgang ; Pandelia, Maria-Eirini (2015)

The regulatory hydrogenase (RH) from Ralstonia eutropha H16 acts as a sensor for the detection of environmental H-2 and regulates gene expression related to hydrogenase-mediated cellular metabolism. In marked contrast to prototypical energy-converting [NiFe] hydrogenases, the RH is apparently insensitive to inhibition by O-2 and CO. While the physiological function of regulatory hydrogenases is...

Concepts in bio-molecular spectroscopy: vibrational case studies on metalloenzymes

Horch, Marius ; Hildebrandt, Peter ; Zebger, Ingo (2015)

Spectroscopic techniques play a major role in the elucidation of structure-function relationships of biological macromolecules. Here we describe an integrated approach for bio-molecular spectroscopy that takes into account the special characteristics of such compounds. The underlying fundamental concepts will be exemplarily illustrated by means of selected case studies on biocatalysts, namely h...

Calculating average surface enhancement factors of randomly nanostructured electrodes by a combination of SERS and impedance spectroscopy

Kozuch, Jacek ; Petrusch, N. ; Gkogkou, Dimitra ; Gernert, Ulrich ; Weidinger, Inez M. (2015)

Polyhedron Ag nanostructures were created on top of a polished Au electrode via step-wise electrodeposition and tested as substrates for SERS spectroscopy. Average Raman enhancement factors were derived by combining SERS measurements with electrochemical impedance spectroscopy (EIS), which is able to determine the electroactive surface area of a randomly nanostructured surface. Depending on the...

H-2-driven biotransformation of n-octane to 1-octanol by a recombinant Pseudomonas putida strain co-synthesizing an O-2-tolerant hydrogenase and a P450 monooxygenase

Lonsdale, Thomas H. ; Lauterbach, Lars ; Malca, Sumire Honda ; Nestl, Bettina M. ; Hauer, Bernhard ; Lenz, Oliver (2015)

An in vivo biotransformation system is presented that affords the hydroxylation of n-octane to 1-octanol on the basis of NADH-dependent CYP153A monooxygenase and NAD(+)-reducing hydrogenase heterologously synthesized in a bacterial host. The hydrogenase sustains H-2-driven NADH cofactor regeneration even in the presence of O-2, the co-substrate of monooxygenase.