Copper(II) complexes formed with sulfonated salan ligands (HSS) have been synthesized, and their coordination chemistry has characterized using pH-potentiometry spectroscopic methods [UV–vis, electron paramagnetic resonance (EPR), electron–electron double (ELDOR)-detected NMR (EDNMR)] in aqueous solution. Several bridging moieties between the two salicylamine functions were introduced, e.g., et...

The cocaine aptamer is a DNA molecule that binds cocaine at the junction of three helices. The bifunctional spectroscopic probe Ç was incorporated independently into three different positions of the aptamer and changes in structure and dynamics upon addition of the cocaine ligand were studied. Nucleoside Ç contains a rigid nitroxide spin label and can be studied directly by electron paramagneti...

The pulsed electron paramagnetic resonance (EPR) methods of electron spin echo envelope modulation (ESEEM) and electron spin echo-electron nuclear double resonance (ESE-ENDOR) are used to investigate the structure of the Photosystem II oxygen-evolving complex (OEC), including the paramagnetic manganese cluster and its immediate surroundings. Recent unpublished results from the pulsed EPR labora...

We present a structurally dynamic model for nucleotide- and actin-induced closure of the actin-binding cleft of myosin, based on site-directed spin labeling and electron paramagnetic resonance (EPR) in Dictyostelium myosin II. The actin-binding cleft is a solvent-filled cavity that extends to the nucleotide-binding pocket and has been predicted to close upon strong actin binding. Single-cystein...

When photosystem II (PSII) is exposed to excess light, singlet oxygen ((1)O(2)) formed by the interaction of molecular oxygen with triplet chlorophyll. Triplet chlorophyll is formed by the charge recombination of triplet radical pair (3)[P680(•+)Pheo(•-)] in the acceptor-side photoinhibition of PSII. Here, we provide evidence on the formation of (1)O(2) in the donor side photoinhibition of PSII...

Bell's theorem applies to the normalizable approximations of original Einstein-Podolsky-Rosen (EPR) state. The constructions of the proof require measurements difficult to perform, and dichotomic observables. By noticing the fact that the four mode squeezed vacuum state produced in type II down-conversion can be seen both as two copies of approximate EPR states, and also as a kind of polarizati...

Through the use of site-directed mutagenesis and chemical rescue, we have identified the proton acceptor for redox-active tyrosine D in photosystem II (PSII). Effects of chemical rescue on the tyrosyl radical were monitored by EPR spectroscopy. We also have acquired the Fourier-transform infrared (FT-IR) spectrum associated with the oxidation of tyrosine D and concomitant protonation of the acc...

Lithium trimethylsilyldiazomethanide and a cobalt (II) precursor with an N-anchored tris-NHC (TIMENmes ) ligand provide access to the nitrilimide 1. Complex 1 was structurally characterized by single-crystal X-ray diffractometry (SC-XRD) its electronic structure examined in detail, including EPR spectroscopy, SQUID magnetometry computational analyses. The desilylation of C-(trimethylsilyl)nitri...