Cryogenic illumination of Photosystem II (PSII) can lead to the trapping of the metastable radical Y Z •, the radical form of the redox-active tyrosine residue D1-Tyr161 (known as Y Z). Magnetic interaction between this radical and the CaMn 4 cluster of PSII gives rise to so-called split electron paramagnetic resonance (EPR) signals with characteristics that are dependent on the S state. We report

Ribonucleotide reductases (RNRs) are essential for DNA synthesis in most organisms. In class-Ic RNR from Chlamydia trachomatis (Ct), a MnFe cofactor in subunit R2 forms the site required for enzyme activity, instead of an FeFe cofactor plus a redox-active tyrosine in class-Ia RNRs, for example in mouse (Mus musculus, Mm). For R2 proteins from Ct and Mm, either grown in the presence of, or reconsti

Ten square-based pyramidal molybdenum complexes with different sulfur donor ligands, that is, a variety of dithiolenes and sulfides, were prepared, which mimic coordination motifs of the molybdenum cofactors of molybdenum-dependent oxidoreductases. The model compounds were investigated by Mo K-edge X-ray absorption spectroscopy (XAS) and (with one exception) their molecular structures were analyze

Metalloradical EPR signals have been found in intact Photosystem II at cryogenic temperatures. They reflect the light-driven formation of the tyrosine Z radical (YZ) in magnetic interaction with the CaMn4 cluster in a particular S state. These so-called split EPR signals, induced at cryogenic temperatures, provide means to study the otherwise transient YZ and to probe the S states with EPR spectro

The electrons extracted from the CaMn4 cluster during water oxidation in photosystem II are transferred to P680+ via the redox-active tyrosine D1-Tyr161 (YZ). Upon YZ oxidation a proton moves in a hydrogen bond toward D1-His190 (HisZ). The deprotonation and reprotonation mechanism of YZ-OH/Y Z-O is of key importance for the catalytic turnover of photosystem II. By light illumination at liquid heli

The redox-active tyrosine residue (YZ) plays a crucial role in the mechanism of the water oxidation. Metalloradical electron paramagnetic resonance (EPR) signals reflecting the light-induced YZ· in magnetic interaction with the CaMn4-cluster in the particular S-state, YZ·SX intermediates, have been found in intact photosystem II. These so-called split EPR signals are induced by illumination at cry

The interaction EPR split signals from photosystem II (PSII) have been reported from the S0, S1, and S3 states. The signals are induced by illumination at cryogenic temperatures and are proposed to reflect the magnetic interaction between YZ• and the Mn 4Ca cluster. We have investigated the formation spectra of these split EPR signals induced in PSII enriched membranes at 5 K using monochromatic l

Methanol binds to the CaMn4 cluster in photosystem II (PSII). Here we report the methanol dependence of the split EPR signals originating from the magnetic interaction between the CaMn4 cluster and the Y Z· radical in PSII which are induced by illumination at 5 K. We found that the magnitudes of the "split S1" and "split S3" signals induced in the S1 and S 3 states of PSII centers, respectively, a

This study investigated the effect of biogenic AgNPs on seed germination and seedling growth of Solanum lycopersicum. Treatment with silver nanoparticles (AgNPs) showed a significantly high germination rate and seedling growth compared to untreated seeds. Furthermore, its bactericidal effect against bacterial pathogen Clavibacter michiganensis subsp. michiganensis (cmm) infection in Solanum lycope

City centre offerings, including shopping, restaurants and cafés, and a lively atmosphere are vital place attributes, which together with several other elements create an attractive place. However, city centre retailing is facing serious competition from e-commerce and external shopping malls, and dying city centres appear to have become a worldwide epidemic in the last decade. To retain visitors

An investigation of the fundamental frequency in Swedish feedback words is presented. It is hypothesised that the F0-pattern differs between words signalling positive and negative feedback-i.e. agreement and disagreement with the utterance of the preceding speaker. When imitating the contrast, the negative feedback word nej 'no' is often produced with a falling F0, stretching over a larger range,

DescriptionHeat Transfer in Aerospace Applications is the first book to provide an overall description of various heat transfer issues of relevance for aerospace applications. The book contains chapters relating to convection cooling, heat pipes, ablation, heat transfer at high velocity, low pressure and microgravity, aircraft heat exchangers, fuel cells, and cryogenic cooling systems.Chapters spe

Using high-resolution synchrotron-radiation-based electron spectroscopy, vibrationally resolved C1s and S2p photoelectron spectra were obtained for the thiophene molecule in the gas phase. The vibrational structures were analyzed in terms of normal modes, and lifetimes were determined for the hole states. This complete analysis enabled to determine the binding energies of the chemically shifted ca

This article discusses some of the opportunities and challenges that the Estonian Council Presidency is facing during its first term in 2017. We also explore how Estonia is likely to appreach this position. The Council presidency provides a position to propagate national interests and an opportunity for leadership within the Council but can also be preceived as a silencer of domestic narrative. We