Andrew Ozarowski

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The phosphorescence and zero field optically detected magnetic resonance (ODMR) of the tryptophan (Trp) residues of alkaline phosphatase from Escherechia coli are examined. Each Trp is resolved optically and identified with the aid of the W220Y mutant and the terbium complex of the apoenzyme. Trp(109), known from earlier work to be the source of(More)
Phosphorescence and optically detected magnetic resonance (ODMR) measurements are reported on four single-tryptophan mutants of lac repressor protein from Escherichia coli: H74W/Wless, W201Y, Y273W/Wless, and F293W/Wless, where Wless represents a protein background containing the double mutation W201Y/W220Y. The single-tryptophan residues are located in the(More)
A high-spin Co(II) complex (3d(7), S = 3/2), Co(PPh(3))(2)Cl(2) (Ph = phenyl), has been investigated in the solid state by both high-frequency and -field electron paramagnetic resonance (HFEPR) and by variable-temperature, variable-field magnetic circular dichroism (VTVH-MCD). In HFEPR spectroscopy, the combination of variable sub-THz frequencies generated(More)
The heterometallic complex [Co(4)Fe(2)OSae(8)]·4DMF·H(2)O (1) was synthesized by one-pot reaction of cobalt powder with iron chloride in a dimethylformamide solution of salicylidene-2-ethanolamine (H(2)Sae) and characterized by single crystal X-ray diffraction analysis, magnetic measurements, high frequency electron paramagnetic resonance (HF-EPR), and(More)
Phosphorescence and optically detected magnetic resonance (ODMR) spectra of tryptophan (W) and several of its analogues (4-, 5-, 6-methyltryptophan (MeW); 4-, 5-, 6-fluorotryptophan (FW); 5-bromotryptophan) are compared with those of complexes formed with the W-free trp aporepressor from Escherichia coli (W19,99F). W19,99F binds W and each analogue except(More)
Ceriporiopsis subvermispora oxalate oxidase (CsOxOx) is the first bicupin enzyme identified that catalyzes manganese-dependent oxidation of oxalate. In previous work, we have shown that the dominant contribution to catalysis comes from the monoprotonated form of oxalate binding to a form of the enzyme in which an active site carboxylic acid residue must be(More)
Bacillus subtilis oxalate decarboxylase (OxDC) catalyzes the conversion of oxalate into CO(2) and formate. The enzyme is composed of two cupin domains, each of which contains a Mn(II) ion. Although there is general agreement that Mn(II) in the N-terminal domain mediates OxDC-catalyzed decarboxylation, legitimate questions have been raised concerning the(More)
Oxalate decarboxylase from Bacillus subtilis is composed of two cupin domains, each of which contains a Mn(II) ion coordinated by four identical conserved residues. The similarity between the two Mn(II) sites has precluded previous attempts to distinguish them spectroscopically and complicated efforts to understand the catalytic mechanism. A multifrequency(More)
Nitric oxide synthase (NOS), a homodimeric enzyme with a flavin reductase domain and a P450-type heme-containing oxygenase domain, catalyzes the formation of NO from L-arginine, NADPH, and O(2) in a two-step reaction sequence. In the first step, a tetrahydrobiopterin (H(4)B) cofactor bound near one of the heme propionate groups acts as an electron donor to(More)