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Research is presented demonstrating the use of high-filed electron paramagnetic resonance at 285 Ghz to explore the tyrosyl radical environment in Mycobacterium tuberculosis protein, from reconstituted and native samples.

A combination of EPR and Mossbauer spectroscopy is employed to explain the presence of inequivalent hemes in the heme sites of tryptophan dioxygenase (TDO). The various properties and structures of the hemes are also explained.

The EPR spectrum of the nitrosyl complex of fully reduced MauG which showed a single six-coordinate Fe(II)-NO species, a characteristic feature of a histidine-ligated Fe(II)-NO moiety in the heme environment is presented. The results provide insight into unprecedented behavior of six-coordinate protein-bound heme for which each of redox states of iron (Fe(II), Fe(III), and Fe(IV)) relevant to the overall catalytic mechanism and the electronic communication between the two iron centers.

The effects of replacing the axial methionine ligand of the type 1 copper site with leucine on the structure and function of amicyanin are examined. The analysis of the structures have shown that the major determinant of the large decrease in the determined values of electronic coupling and the temperature dependence of the electron transfer rate is the increased distance from the copper to the protein within the type 1 site of M98L amicyanin.

The purification and isolation of a homologous enzyme from Pseudomonas syringae, whose encoding gene (orf3) shares a relatively low degree of sequence homology with the corresponding (S)-2-hydroxypropylphosphonic acid (HPP) epoxidase (Sw-HppE) gene in Streptomyces wedmorensis is reported. The purified Pseudomonas syringae protein is found to catalyze the epoxidation of (S)-HPP to fosfomycin and the oxidation of (R)-HPP to 2-oxopropylphosphonic acid under the same conditions as Sw-HppE.

A study was conducted to characterize the interaction between accessory gene, mauG and its biosynthetic precursor protein substrate. The results provided insights into kinetic parameters for unusual reaction of mauG with protein substrate and protein product and conformation changes in protein during catalysis, which affect the protein-protein interactions.

Several close homologues of [alpha]-amino-[beta]-carboxymuconate-[epsilon]-semialdehyde decarboxylase (ACMSD) were analyzed to study transition metal-catalyzed nonoxidative decarboxyaltion reactions. The enzyme homologues of ACMSD are involved in the catabolism of tryptophan and vanillate, the biodegradation of hydroxylbenzoates, and the thymidine salvage pathways in certain organisms.

The high-resolution crystal structure of [alpha]-amino-[beta]-carboxymuconate-[epsilon]-semialdehyde decarboxylase (ACMSD) from Pseudomonas fluorescence is described. The structure of the enzyme shows the precise spatial arrangement of the active site metal center and identifies a potential substrate-binding pocket and the hydrogen bonding network around the metal center suggests that Arg51 and His228 may play important role in catalysis.

A comprehensive protein sequence analysis has exhibited a strong link between Pseudomonas fluorescens [alpha]-amino-[beta]-carboxymuconic-[epsilon]-semialdehyde decarboxylase (ACMSD) and the metal-dependent amidohydrolase protein superfamily. ACMSD is the first characterized member in the amidohydrolase superfamily that represents a C-C breaking activity.

The mechanism by which 4-Chloro-3-hydroxyanthranilate inhibits the 3-Hydroxyanthranilate-3,4-dioxygenase (HAD) catalyzed reaction is described. 4-Chloro-3-hydroxyanthranilate functions as a mechanism-based inactivating agent is demonstrated using overexpressed and purified bacterial HAD.