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Multitouch experiment instructions (MEIs), implemented as interactive eBooks, are learning tools for pupils that offer various digital support tools and enable pupils to individualize their learning. They may be applied to contexts such as inquiry-based experiments in school laboratories, which involve highly demanding cognitive processes and require a high level of self-regulation. Self-regulation has been shown to be reliably promoted by interventions which include the targeted training of self-regulation strategies. A MEI was designed as an interactive eBook on experiments on the topic "Analysis of Cola", suitable for an inquiry-based learning environment such as a school lab. The MEI's potential to promote self-regulated learning was investigated by comparing it to a MEI with digital, integrated self-regulation training. The data revealed a significant increase of self-regulation in the control group, which consisted of pupils experimenting with the MEI on its own, and one experimental group, which included pupils that were supported by the MEI with an additional self-regulation training. It can be assumed that the MEI's ability to promote self-regulated learning is comparable to the results achieved by an additional self-regulation training which explicitly addressed self-regulation strategies. This highlights the MEI's potential to promote self-regulated learning in an indirect approach.

Organic semiconductors are studied intensively for applications in electronics and optics (1), and even spin-based information technology, or spintronics (2). Fundamental quantities in spintronics are the population relaxation time ([T.sub.1]) [...]

Gram-negative pathogens commonly interact with their environment using long, linear, surface-exposed protein appendages called pili. In uropathogenic Escherichia coli, type 1 pili carry at their distal end a dedicated mannose-specific [...], Type 1 pili are the archetypal representative of a widespread class of adhesive multisubunit fibres in Gram-negative bacteria. During pilus assembly, subunits dock as chaperone-bound complexes to an usher, which catalyses their polymerization and mediates pilus translocation across the outer membrane. Here we report the crystal structure of the full-length FimD usher bound to the FimC-FimH chaperone-adhesin complex and that of the unbound form of the FimD translocation domain. The FimD-FimC-FimH structure shows FimH inserted inside the FimD 24-stranded β-barrel translocation channel. FimC-FimH is held in place through interactions with the two carboxy-terminal periplasmic domains of FimD, a binding mode confirmed in solution by electron paramagnetic resonance spectroscopy. To accommodate FimH, the usher plug domain is displaced from the barrel lumen to the periplasm, concomitant with a marked conformational change in the β-barrel. The amino-terminal domain of FimD is observed in an ideal position to catalyse incorporation of a newly recruited chaperone-subunit complex. The FimD-FimC-FimH structure provides unique insights into the pilus subunit incorporation cycle, and captures the first view of a protein transporter in the act of secreting its cognate substrate.

The presence of an oxygen-dependent free radical is demonstrated in the thiamine diphosphate-dependent Escherichia coli 2-oxoglutarate dehydrogenase, which is a key component of the tricarboxylic acid (Krebs) cycle. The off-pathway reaction has accounted for metabolic dysfunction associated with many neurodegenerative diseases.

Binding of methanol to the quinoprotein ethanol dehydrogenase from Pseudomonas aeruginosa has been studied by pulsed electron-nuclear double resonance at 9 GHz. Shifts in the hyperfine couplings of the pyrroloquinoline quinone radical provide direct evidence for a change in the environment of the cofactor when substrate is present. By performing experiments with deuteriated methanol, we confirmed that methanol was the cause of the effect. Density functional theory calculations show that these shifts can be understood if a water molecule, which is often found in x-ray structures of the active site of quinoprotein alcohol dehydrogenases, is displaced by the substrate. The difference between the binding of water and methanol is that the water molecule forms a hydrogen bond to 05 of pyrroloquinoline quinone, which the methanol, by virtue of its methyl group, does not. The results support the proposal that aspartate rather than glutamate is the catalytically active base for a hydride transfer mechanism in quinoprotein alcohol dehydrogenases. pyrroloquinoline quinone | alcohol dehydrogenase | density functional theory | methanol | electron paramagnetic resonance

The blue-light sensitive photoreceptor, phototropin, is a flavoprotein, which regulates the phototropism response of higher plants. The photoinduced triplet state and the photoreactivity of the flavin-mononucleotide (FMN) cofactor in two LOV domains are studied. The differences in the electronic structure of the FMN can be attributed to the changes in the amino-acid composition of the binding LOV1 and LOV2 domains.

The light-induced electron transfer reaction of flavin cofactor photoactivation in Xenopus laevis (6-4) photolyase has been studied by continuous-wave and time-resolved electron paramagnetic resonance spectroscopy. When the photoactivation is initiated from the fully oxidized form of the flavin, a neutral flavin radical is observed as a long-lived paramagnetic intermediate of two consecutive single-electron reductions under participation of redox-active amino acid residues. By time-resolved electron paramagnetic resonance, a spin-polarized transient radical-pair signal was detected that shows remarkable differences to the signals observed in the related cyclobutane pyrimidine dimer photolyase enzyme. In (6-4) photolyase, a neutral tyrosine radical has been identified as the final electron donor, on the basis of the characteristic line width, hyperfine splitting pattern, and resonance magnetic field position of the tyrosine resonances of the transient radical pair.

Research is presented concerning the use of the density functional theory for the calculation of the electronic structure of FADH, a neutral falvin radical which is formed during DNA repair in photolyase.

The characterization of the FAD cofactor of Escherichia coli DNA photolyase by EPR spectroscopy has been carried out. Data about spin density distributions in the benzene and pyrazine rings of the flavin are presented.

The RNA polymerases (RNAP)-F/E subcomplex is described, which has formed a stable heterodimer that has bound the nascent RNA and has stimulated the processivity of elongation complexes. The pulsed-EPR method DEER and fluorescence spectroscopy have shown that, upon binding of RNA, F/E has remained in a stable conformation, suggesting that it has served as a structurally rigid guiding rail for the growing RNA chain during transcription.

The pulsed EPR technique of double electron electron resonance (DEER) is used for probing the distribution of intramolecular end-to-end distances. The results have shown that porphyrin-based molecular wires are shape-persistent, but their shapes can be deformed by binding to multivalent ligands.

Continuous wave electron paramagnetic resonance is performed on the radical form of monoamine oxidase (MAO) A in order to characterize the anionic flavin radical. The similar electronic structures and hydrophobic environments of MAO and D-amino acid oxidase (DAAO) and the similar structural motifs of their substrates have shown that a direct hydride transfer catalytic mechanism of DAAO should be considered for MAO.

An analysis is conducted to determine whether the distance longer than 2.6 nm between two metal centers in human serum transferrin and lactoferrin, can be found by pulsed electron-electron double resonance (ELDOR). It was demonstrated that pulsed ELDOR can be applied to find distances greater than 4 nm between copper sites in proteins.

Pulsed electron-electron double resonance (ELDOR) is used to obtain structural information from Augmenter of Liver Regeneration (ALR), which is a homodimeric FAD-dependent sulfhydryl oxidase. The relaxation behavior, the depth and slow decay of the ELDOR modulations show that flavins have excellent properties to be used as natural spin labels for distance determinations by pulsed ELDOR.

The orientation of the g-matrix of FADH. is determined by electron-nuclear double resonance (ENDOR) at 95 GHz and 3.5 T. At such high values of the microwave frequency and the magnetic field, the g-anisotropy provides improved EPR spectral resolution compared to experiments performed at conventional 9.5 GHz and 0.35 mT.

A study proposes two mechanisms for the reduction of substrate in quinoprotein alcohol dehydrogenases, which are carried out by the cofactor pyrroloquinoline quinone (PQQ) and initiated by amino acid base-catalyzed proton abstraction of the hydroxyl proton of ethanol. The first direct evidence for the tight binding of ethanol to a PQQ-dependent alcohol dehydrogenase is gained by the use of increased spectral resolution of high-field electron paramagnetic resonance (EPR).

In the flavin mononucletide-binding LOV1 domain of the Phot1-receptor from Chlamydomonas reinhardtii the photoreactive cysteine C57 has been replaced by methionine. Photoexcitation of this C57M mutant yields a metastable photoproduct (C57M-415) that thermally decomposes into a stable paramagnetic species (C57M-675) with extremely red-shifted absorption in the visible range. In this contribution, we describe the characterization of this radical by multi-frequency electron paramagnetic resonance and electron-nuclear double resonance. The main features of the spectra identify the paramagnetic species as a flavin neutral radical. However, detailed analysis shows that the isoalloxazine moiety of the flavin is alkyl substituted at N(5), rather than protonated as is usually the case. The implication of these observations on the likely mechanism of photoproduct generation in wild-type LOV domains is discussed. [ABSTRACT FROM AUTHOR]