Cryptochromes are a class of flavoprotein blue-light signaling receptors found in plants, animals, and humans that control plant development the entrainment circadian rhythms. In cryptochromes, light activation is proposed to result from photoreduction protein-bound flavin chromophore through intramolecular electron transfer. However, although similar structure light-response mechanism animal cryptochromes remains entirely unknown. To complicate matters further, there currently debate on...

The perhalogenated closo-dodecaborate dianions [B12 X12 ](2-) (X=H, F, Cl, Br, I) are three-dimensional counterparts to the two-dimensional aromatics C6 X6 I). Whereas oxidation of parent compounds H12 and benzene does not lead isolable radicals, analogues can be oxidized by chemical or electrochemical methods give stable radicals. with strong oxidizer AsF5 in liquid sulfur dioxide (lSO2 ) yielded corresponding radical anions ](⋅-) (X=F, Br). presence ions was proven EPR UV/Vis spectroscopy...

The biogenesis of the photosynthetic apparatus in developing seedlings requires assembly proteins encoded on both nuclear and chloroplast genomes. To coordinate this process there needs to be communication between these organelles, but retrograde signals by which communicates with nucleus at time are still essentially unknown. Arabidopsis thaliana genomes uncoupled ( gun ) mutants, that show elevated gene expression after damage, have formed basis our understanding signaling. Of 6 reported...

Strong as an ox: Oxidation of the perchlorinated dodecaborate [B12Cl12]2− by AsF5 in liquid sulfur dioxide leads to Jahn–Teller-distorted radical anion [B12Cl12].− and neutral B12Cl12 (see structure; B brown, Cl green). The formation both compounds has been verified a combination several theoretical experimental methods (pictured: cyclic voltammogram SO2).

Plants coordinate their responses to various biotic and abiotic stresses in order optimize developmental acclimatory programmes. The ultimate response an excessive amount of stress is local induction cell death mechanisms. certain cells can help maintain tissue homeostasis enable nutrient remobilization, thus increasing the survival chances whole organism unfavourable environmental conditions. UV radiation one factors that negatively affects photosynthetic process triggers death. aim this...

The titanium(III)-catalyzed cross-coupling between ketones and nitriles provides an efficient stereoselective synthesis of α-hydroxyketones. A detailed mechanistic investigation this reaction is presented, which involves a combination several methods such as EPR, ESI-MS, X-ray, in situ IR kinetics, DFT calculations. Our findings reveal that C-C bond formation turnover-limiting occurs by catalyst-controlled radical involving two titanium(III) species. resting state identified cationic...

Abstract The straightforward synthesis of the cationic, purely organometallic Ni I salt [Ni(cod) 2 ] + [Al(OR F ) 4 − was realized through a reaction between and Ag[Al(OR (cod=1,5‐cyclooctadiene). Crystal‐structure analysis EPR, XANES, cyclic voltammetry studies confirmed presence homoleptic olefin complex. Weak interactions metal center, ligands, anion provide good starting material for further cationic complexes.

The ptm mutant of Arabidopsis does not show a genomes uncoupled phenotype and PTM is therefore unlikely to function in chloroplast-to-nucleus signaling as previously reported.

Selective degradation of mitochondria by autophagy (mitophagy) is thought to play an important role in mitochondrial quality control, but our understanding which conditions induce mitophagy plants limited. Here, we developed novel reporter lines monitor and surveyed the rate under a wide range stresses developmental conditions. Especially carbon starvation induced dark-incubation causes dramatic increase within few hours, further increasing as dark-induced senescence progresses. Natural was...

The Escherichia coli ribonucleotide reductase (RNR) catalyzes the conversion of nucleoside diphosphates to deoxynucleotides and requires a diferric-tyrosyl radical cofactor for catalysis. RNR is composed 1:1 complex two homodimeric subunits: alpha beta. Incubation E441Q-alpha mutant with substrate CDP allosteric effector TTP results in loss tyrosyl formation new radicals on 200 ms min time scale. first was previously established by stopped flow UV/vis spectroscopy pulsed high field EPR be...

Impaired mitochondrial translation or reduced protein import can lead to imbalances in composition. Such proteotoxic stresses trigger a nuclear transcriptional response commonly described as the unfolded (UPR mt ). Despite extensive studies of UPR pathways animal and fungal systems, very little is known about how regulated plants. Through comparison Arabidopsis thaliana whole-genome transcriptome data, it was found that most genes induced by ribosome inhibitor doxycycline are also Complex...

Mitochondria play essential roles in plant metabolism, supporting both development and stress responses. To maintain a healthy pool of mitochondria, several quality control systems are place. Selected degradation mitochondria by autophagy -mitophagy- has been extensively studied yeast animals, but information on mitophagy components plants is limited. The 'Friendly Mitochondria' (FRIENDLY; FMT) protein, homologous to 'clustered protein homolog' CLU was recently suggested mediate depolarized...

Plants, being sessile organisms, constantly need to respond environmental stresses, often leading the accumulation of reactive oxygen species (ROS). While ROS can be harmful, they also act as second messengers guiding plant growth and stress responses. Because chloroplasts are sensitive changes both a source target during conditions, important in conveying nucleus, where acclimation responses coordinated maintain organellar overall cellular homeostasis. ANAC102 has previously been...

Ribonucleotide reductases (RNRs) catalyze the conversion of nucleotides to deoxynucleotides providing monomeric precursors required for DNA replication and repair. The class I RNRs are composed two homodimeric subunits: R1 R2. has active site where nucleotide reduction occurs, R2 contains diiron tyrosyl radical (Y•) cofactor essential initiation on R1. Mechanism-based inhibitors, such as 2'-azido-2'-deoxyuridine-5'-diphosphate (N3UDP), have provided much insight into mechanism. N3UDP is a...

Starke Oxidationsmittel: Die Oxidation des perchlorierten Dodecaborates [B12Cl12]2− mit AsF5 in flüssigem Schwefeldioxid führt zum Jahn-Teller-verzerrten Radikalanion [B12Cl12].− und zu neutralem B12Cl12 (siehe Struktur; braun B, grün Cl). Bildung beider Verbindungen wurde experimentell theoretisch nachgewiesen. Das Bild zeigt das Cyclovoltammogramm von SO2. Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents peer-reviewed, but not...

The dinuclear doubly azole-bridged copper(II) complexes [Cu(II)2(L)2(MeCN)4](ClO4)4·3.73MeCN·0.80H2O and [Cu(II)2(L)6](ClO4)4·solvent (solvent = 2MeCN·H2O; 2MeCN·2H2O; 1.5MeOH·3.5H2O) were prepared [L 3-(6-methyl-2-pyridyl)-[1,2,4]triazolo[4,3-a]pyridine]. Structural characterizations revealed very different local geometries about the ions, being trigonal bipyramidal for former (τ 0.76) square pyramidal latter 0.07, 0.15, 0.07) complex. Magnetic measurements of bulk material...

Phototropin is a flavin mononucleotide (FMN) containing blue-light receptor, which regulates, governed by its two LOV domains, the phototropic response of higher plants. Upon photoexcitation, FMN cofactor triplet state, 3F, reacts with nearby cysteine to form covalent adduct. Cysteine-to-alanine mutants domains instead generate radical upon illumination. Here, we explore formation photochemically induced dynamic nuclear polarization (CIDNP) in LOV2-C450A Avena sativa phototropin and...

Recent multifrequency EPR studies of the "high-affinity" quinone binding site quinol oxidase (Q(H) site) have suggested a very asymmetric hydrogen-bonding environment for semiquinone radical anion state. Single-sided hydrogen bonding to O1 carbonyl position was one proposals, which contrasts with some previous experimental indications. Here density functional calculations parameters (g-tensors, 13C, 1H, and 17O hyperfine tensors) wide variety supermolecular model complexes been used provide...

Abstract The recently published purely metallo‐organic Ni I salt [Ni(cod) 2 ][Al(OR F ) 4 ] ( 1 , cod=1,5‐cyclooctadiene, R =C(CF 3 provides a starting point for new synthesis strategy leading to phosphine complexes, replacing cod ligands by phosphines. Clearly visible colour changes indicate reactions within minutes, while quantum chemical calculations (PBE0‐D3(BJ)/def2‐TZVPP) approve exergonic reaction enthalpies in all performed ligand exchange reactions. Hence, [Ni(dppp)...

The optical emission properties of the lanthanoid catena-polyphosphates Ln(PO(3))(3) (Ln = Y, Gd, Lu) doped with europium were investigated. Incommensurately modulated β-Y(PO(3))(3):Eu (super space group Cc (0|0.364|0)0) and Gd(PO(3))(3):Eu (space I2/a) show usual characteristics Eu(3+), while in Lu(PO(3))(3):Eu Cc) is unprecedentedly partially reduced to divalent state, as proven by both a broad band at 406 nm excited 279 an EPR spectroscopic investigation. (151)Eu-Mössbauer spectroscopy...

We investigated the lumazine protein from Photobacterium leiognathi in complex with its biologically active cofactor, 6,7-dimethyl-8-ribityllumazine, at different redox states and compared results samples containing a riboflavin cofactor. Using anaerobic photoreduction, we were able to record optical absorption kinetics both cofactors similar environments. It could be demonstrated that is stabilize neutral ribolumazine radical ∼35% yield. The state was further by W-band continuous-wave EPR...

Bacterial phytochromes are dimeric light-regulated histidine kinases that convert red light into signaling events. Light absorption by the N-terminal photosensory core module (PCM) causes proteins to switch between two spectrally distinct forms, Pr and Pfr, thus resulting in a conformational change modulates C-terminal kinase region. To provide further insights structural details of photoactivation, we investigated full-length Agp1 bacteriophytochrome from soil bacterium Agrobacterium fabrum...

Abstract The straightforward synthesis of the cationic, purely organometallic Ni I salt [Ni(cod) 2 ] + [Al(OR F ) 4 − was realized through a reaction between and Ag[Al(OR (cod=1,5‐cyclooctadiene). Crystal‐structure analysis EPR, XANES, cyclic voltammetry studies confirmed presence homoleptic olefin complex. Weak interactions metal center, ligands, anion provide good starting material for further cationic complexes.

In recent years, photoexcited molecular triplet states became increasingly popular in magnetic resonance, e.g. as spin probes to measure distances relative other electron-paramagnetic species or moieties that transfer light-generated electron–spin polarisation of the state surrounding nuclei. this study, three commercially available dyes, Erythrosin B, Rose Bengal and Atto Thio 12, all typically utilised fluorophores optical spectroscopies microscopies, are investigated aqueous solutions by...