We report the first (55)Mn pulsed ENDOR studies on the S2 state multiline spin ½ centre of the oxygen evolving complex (OEC) in Photosystem II (PS II), at temperatures below 4.2 K. These were performed on highly active samples of spinach PS II core complexes, developed previously in our laboratories for photosystem spectroscopic use, at temperatures down to 2.5 K. Under these conditions, relaxa...

In situ immobilization of poly[N-(4-carboxyphenyl)methacrylamide] has been performed on silica gel surface. Infrared (IR) and mass spectroscopies as well as thermogravimetry (TG) analysis have been used to elucidate the structure of immobilized polymer. An adsorption capacity of the synthesized composite towards Cu(II), Pb(II), Mn(II), Fe(III), Co(II), and Ni(II) ions has been estimated. Adsorp...

In the title compound, [Mn(C(8)H(2)NO(6))(H(2)O)(2)](n), each pyridine-2,4,6-tricarboxyl-ate (tpc) ligand bridges two Mn(II) ions with the formation of polymeric chains located on a twofold rotation axis. Each Mn(II) ion is coordinated by two O and one N atoms from one tpc ligand, two O atoms from another ligand and two water mol-ecules in a distorted penta-gonal-bipyramidal geometry. The Mn-N ...

For some time, the presence of high oxidation state Mn ions and Ca(II) in active center Photosystem II has been known. However, coordination complexes that combine both Mn(III) have difficult to obtain, with only a handful examples reported. In this paper we report synthesis two new Mn(III)-Ca(II) complexes, 1 [Pr2NH2]3[Mn6CaO2(OH)(OMe)3(SALO)6 (SALOH)3] 2 [Mn18Ca6O12(OH)6(MeO)12(PhCOO)18(MeOH)...

The anthracis repressor (AntR) is a manganese-activated transcriptional regulator from Bacillus anthracis and is a member of the diphtheria toxin repressor (DtxR) family of proteins. In this paper, we characterize the Mn(II) binding and protein dimerization state using a combination of continuous wave (cw) and pulsed EPR methods. Equilibrium metal binding experiments showed that AntR binds 2 eq...

Calprotectin (CP) is a transition metal-chelating antimicrobial protein of the calcium-binding S100 family that is produced and released by neutrophils. It inhibits the growth of various pathogenic microorganisms by sequestering the transition metal ions manganese and zinc. In this work, we investigate the manganese-binding properties of CP. We demonstrate that the unusual His(4) motif (site 2)...

A simple tandem mass spectrometry method for differentiating isomeric monoglycosyl flavonols, flavones, and flavanones using manganese complexation is reported. Dissociation of the [Mn(II) (L) (L - H)]+ and [Mn(II) (L)2 (L - H)]+ species provides unique fragment ions that allow the identification of the saccharide moiety as glucose, galactose, arabinose, or xylose. The glycosylation site of the...

The asymmetric unit of the title coordination polymer, {[Mn(C(6)Cl(2)O(4))(C(10)H(8)N(2))]·2C(2)H(5)OH}(n), consists of one Mn(II) ion, one 2,2'-bipyridine (bpy) ligand, one chloranilate (CA(2-)) ligand and two ethanol solvent mol-ecules. The Mn(II) ion is octa-hedrally coordinated by two N atoms of one bpy ligand and four O atoms of two chloranilate ions. The chloranilate ion serves as a bridg...

The synthesis, structures and magnetic properties of two new mixed-valence heptanuclear manganese clusters are described. Both complexes utilize triethanolamine (teaH(3)) as a bridging ligand, displaying near planar, disc-like metal topologies and are of formulae [Mn(II)(4)Mn(IV)(3)(tea)(teaH(2))(3)(peolH)(4)](BF(4))(2)·solv (1) and [Mn(II)(4)Mn(III)(3)F(3)(tea)(teaH)(teaH(2))(2)(piv)(4)(Hpiv)(...

The title complex, [Mn(2)(C(18)H(4)O(10))(H(2)O)(4)](n), was synthesized from manganese(II) chloride tetra-hydrate and 9,10-dioxo-9,10-dihydro-anthracene-1,4,5,8-tetra-carb-oxy-lic acid (H(4)AQTC) in water. The anthraquinone unit is located about a crystallographic center of inversion. Each asymmetric unit therefore contains one Mn(II) atom, two water ligands and one half AQTC(4-) anion. The Mn...