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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
Detailed optical and EPR analyses of states induced in dark-adapted PS II membranes by cryogenic illumination permit characterization and quantification of all pigment derived donors and acceptors, as well as optically silent (in the visible, near infrared) species which are EPR active. Near complete turnover formation of QA- is seen in all centers, but with variable efficiency, depending on the d
EPR spectroscopy is very useful in studies of the oxygen evolving cycle in Photosystem II and EPR signals from the CaMn4 cluster are known in all S states except S4. Many signals are insufficiently understood and the S0, S1, and S3 states have not yet been quantifiable through their EPR signals. Recently, split EPR signals, induced by illumination at liquid helium temperatures, have been reported
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
Water oxidation in photosystem II is catalyzed by the CaMn4 cluster. The electrons extracted from the CaMn4 cluster are transferred to P680+ via the redox-active tyrosine residue D1-Tyr161 (YZ). The oxidation of YZ is coupled to a deprotonation creating the neutral radical YZ•. Light-induced oxidation of YZ is possible down to extreme temperatures. This can be observed as a split EPR signal from Y
The photosystem II (PSII) reaction center contains two redox active tyrosines, YZ and YD, situated on the D1 and D2 proteins, respectively. By illumination at 5 K, oxidation of YZ in oxygen-evolving PSII can be observed as induction of the Split S1 EPR signal from YZ• in magnetic interaction with the CaMn4 cluster, whereas oxidation of YD can be observed as the formation of the free radical EPR si
S-State-dependent split EPR signals that are induced by illumination at cryogenic temperatures (5 K) have been measured in spinach photosystem II without interference from the YD• radical in the g ∼ 2 region. This allows us to present the first decay-associated spectra for the split signals, which originate from the CaMn4 cluster in magnetic interaction with a nearby radical, presumably YZ•. The t
En artlista inkluderande de arter som noterades vid en exkursion till Fridö i Södermanland 2018 presenterades tidigare i Lavbulletinen. Några arter var då ännu inte bestämda eller bara preliminärt bestämda. Här kompletteras artlistan med Bacidina egenula (ny för Södermanland) och Rinodina calcarea (första fyndet utanför Öland och Gotland) vilken nu är konfirmerad genom DNA-analys.
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 sophisticated book presents new theoretical and analytical insights into the momentous events in the Arab world that began in 2011 and, more importantly, into life and politics in the aftermath of these events. Focusing on the qualities of the sensory world, Maria Frederika Malmström explores the dramatic differences after the Egyptian revolution and their implications for society—the lack of
We develop a new scheme for the construction of explicit complex-valued proper biharmonic functions on Riemannian Lie groups. We exploit this and manufacture many infinite series of uncountable families of new solutions on the special unitary group SU(n). We then show that the special orthogonal group SO(n) and the quaternionic unitary group Sp(n) fall into the scheme. As a by-product we obtain
The aim of this study was to investigate how solar drying setup and choice of juice pretreatment determine the drying flux in a fruit juice concentration process called solar assisted pervaporation. With this process, hygienic membrane pouches and solar energy are used to concentrate and preserve fruit juices. In this study, the feasibility of concentrating citrus (tangerine) juice into marmalade
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,
