An inhibitor of FtsZ with potent and selective anti-staphylococcal activity.

FtsZ is an essential bacterial guanosine triphosphatase and homolog of mammalian beta-tubulin that polymerizes and assembles into a ring to initiate cell division. We have created a class of small synthetic antibacterials, exemplified by PC190723, which inhibits FtsZ and prevents cell division. PC190723 has potent and selective in vitro bactericidal activity against staphylococci, including methicillin- and multi-drug-resistant Staphylococcus aureus.

High-field EPR investigations of Mn(III)Mn(IV) and Mn(II)Mn(III) states of dimanganese catalase and related model systems.

Multi-frequency EPR experiments at 9, 34 and 94 GHz are reported on the antiferromagnetically coupled mixed valence Mn(II)Mn(III) complex of manganese catalase and on several dinuclear manganese model systems. They are compared with similar experiments obtained earlier for the Mn(III)Mn(IV) states. It is demonstrated how accurate information on the G- and 55Mn hyperfine tensors can be derived from this approach.

Substrate specificity and mechanism from the structure of Pyrococcus furiosus galactokinase.

Galactokinase (GalK) catalyses the first step of the Leloir pathway of galactose metabolism, the ATP-dependent phosphorylation of galactose to galactose-1-phosphate. In man, defects in galactose metabolism can result in disorders with severe clinical consequences, and deficiencies in galactokinase have been linked with the development of cataracts within the first few months of life. The crystal structure of GalK from Pyrococcus furiosus in complex with MgADP and galactose has been determined to 2.

Outer sphere mutagenesis of Lactobacillus plantarum manganese catalase disrupts the cluster core. Mechanistic implications.

X-ray crystallography of the nonheme manganese catalase from Lactobacillus plantarum (LPC) [Barynin, V.V., Whittaker, M.

The structures of Micrococcus lysodeikticus catalase, its ferryl intermediate (compound II) and NADPH complex.

The crystal structure of the bacterial catalase from Micrococcus lysodeikticus has been refined using the gene-derived sequence both at 0.88 A resolution using data recorded at 110 K and at 1.5 A resolution with room-temperature data.

E. coli aconitase B structure reveals a HEAT-like domain with implications for protein-protein recognition.

The major bifunctional aconitase of Escherichia coli (AcnB) serves as either an enzymic catalyst or a mRNA-binding post-transcriptional regulator, depending on the status of its iron sulfur cluster. AcnB represents a large, distinct group of Gram-negative bacterial aconitases that have an altered domain organization relative to mitochondrial aconitase and other aconitases. Here the 2.

Crystal structure of manganese catalase from Lactobacillus plantarum.

Background: Catalases are important antioxidant metalloenzymes that catalyze disproportionation of hydrogen peroxide, forming dioxygen and water. Two families of catalases are known, one having a heme cofactor, and the other, a structurally distinct family containing nonheme manganese. We have solved the structure of the mesophilic manganese catalase from Lactobacillus plantarum and its azide-inhibited complex.

The structure and domain organization of Escherichia coli isocitrate lyase.

Enzymes of the glyoxylate-bypass pathway are potential targets for the control of many human diseases caused by such pathogens as Mycobacteria and Leishmania. Isocitrate lyase catalyses the first committed step in this pathway and the structure of this tetrameric enzyme from Escherichia coli has been determined at 2.1 A resolution.

Antibiotic activity and characterization of BB-3497, a novel peptide deformylase inhibitor.

Peptide deformylase (PDF) is an essential bacterial metalloenzyme which deformylates the N-formylmethionine of newly synthesized polypeptides and as such represents a novel target for antibacterial chemotherapy. To identify novel PDF inhibitors, we screened a metalloenzyme inhibitor library and identified an N-formyl-hydroxylamine derivative, BB-3497, and a related natural hydroxamic acid antibiotic, actinonin, as potent and selective inhibitors of PDF. To elucidate the interactions that contribute to the binding affinity of these inhibitors, we determined the crystal structures of BB-3497 and actinonin bound to Escherichia coli PDF at resolutions of 2.

Interaction of nitric oxide with the oxygen evolving complex of photosystem II and manganese catalase: a comparative study.

We compare the interaction of nitric oxide with the S states of the oxygen evolving complex (OEC) of photosystem II and the dinuclear Mn cluster of Thermus thermophilus catalase. Flash fluorescence studies indicate that the S3 state of the OEC in the presence of ca. 0.

The oxidized (3,3) state of manganese catalase. Comparison of enzymes from Thermus thermophilus and Lactobacillus plantarum.

Manganese catalases contain a binuclear manganese cluster that catalyzes the redox dismutation of hydrogen peroxide, interconverting between dimanganese(II) [(2,2)] and dimanganese(III) [(3,3)] oxidation states during turnover. We have investigated the oxidized (3,3) states of the homologous enzymes from Thermus thermophilus and Lactobacillus plantarum using a combination of optical absorption, CD, MCD, and EPR spectroscopies as sensitive probes of the electronic structure and protein environment for the active site metal clusters. Comparison of results for these two enzymes allows the essential features of the active sites to be recognized and the differences identified.

The structure of SAICAR synthase: an enzyme in the de novo pathway of purine nucleotide biosynthesis.

Background: The biosynthesis of key metabolic components is of major interest to biologists. Studies of de novo purine synthesis are aimed at obtaining a deeper understanding of this central pathway and the development of effective chemotherapeutic agents. Phosphoribosylaminoimidazolesuccinocarboxamide (SAICAR) synthase catalyses the seventh step out of ten in the biosynthesis of purine nucleotides.

Structure of the heme d of Penicillium vitale and Escherichia coli catalases.

A heme d prosthetic group with the configuration of a cis-hydroxychlorin gamma-spirolactone has been found in the crystal structures of Penicillium vitale catalase and Escherichia coli catalase hydroperoxidase II (HPII). The absolute stereochemistry of the two heme d chiral carbon atoms has been shown to be identical. For both catalases the heme d is rotated 180 degrees about the axis defined by the alpha-gamma-meso carbon atoms, with respect to the orientation found for heme b in beef liver catalase.

Site-directed replacement of the coaxial heme ligands of bacterioferritin generates heme-free variants.

The bacterioferritin (BFR) of Escherichia coli is a heme-containing iron storage molecule. It is composed of 24 identical subunits, which form a roughly spherical protein shell surrounding a central iron storage cavity. Each of the 12 heme moieties of BFR possesses bis-methionine axial ligation, a heme coordination scheme so far only found in bacterioferritins.

Pulsed EPR studies of the binuclear Mn(III)Mn(IV) center in catalase from Thermus thermophilus.

The nature of possible protein ligands to the binuclear metal core in manganese catalase from Thermus thermophilus has been addressed by EPR and ESEEM (pulsed EPR) spectroscopies. The three-pulse ESEEM spectrum of the superoxidized Mn(III)Mn(IV) enzyme obtained at 3429 G shows a frequency pattern with peaks at 0.60, 1.

Determination of the metal ion separation and energies of the three lowest electronic states of dimanganese (II,II) complexes and enzymes: catalase and liver arginase.

The dimanganese (II,II) catalase from Thermus thermophilus, MnCat(II,II), arginase from rat liver, Arg(II,II), and several dimanganese(II,II) compounds, LMn2XY2, which are functional catalase mimics, all possess a pair of coupled Mn(II) ions in their catalytic sites. For each of these, we have measured by EPR spectroscopy the relative energies separating the three lowest electronic states (singlet, triplet, and quintet), described a general method for extracting the individual spectra for these states by multicomponent analysis, and determined the Mn-Mn separation. The triplet-singlet and quintet-singlet energy gaps were modeled well by fitting the temperature dependence of the EPR intensities to a Boltzmann expression for a pair of Mn(II) ions coupled by isotropic Heisenberg spin exchange (-2JS1S2).

Protein coordination to manganese determines the high catalytic rate of dimanganese catalases. Comparison to functional catalase mimics.

Catalysis of hydrogen peroxide dismutation by the dimanganese catalase from Thermus thermophilus has been measured and found to obey Michaelis-Menton kinetics with no evidence for substrate inhibition at concentrations up to 0.45 M H2O2. Comparison among three dimanganese catalases (Thermus thermophilus, Thermoleophilium album, and Lactobacillus plantarum) reveals that their apparent second-order rate constants, Kcat/Km, differ by at most a factor of 5, even though the individual kinetic constants differ by as much as a factor of 20.

The dimanganese(III,IV) oxidation state of catalase from Thermus thermophilus: electron nuclear double resonance analysis of water and protein ligands in the active site.

The 1H hyperfine tensors of the dimanganese(III,IV) oxidation state of the non-heme-type catalase enzyme from the thermophilic bacterium Thermus thermophilus have been measured by electron nuclear double resonance (ENDOR) spectroscopy at pH 6.5-9. These were compared to model dimanganese(III,IV) complexes possessing six-coordinate N4O2, N3O3, and O6 atom donor sets to each Mn and mu-oxo and mu-carboxylato bridging ligands.

Three-dimensional structure of catalase from Micrococcus lysodeikticus at 1.5 A resolution.

The three-dimensional crystal structure of catalase from Micrococcus lysodeikticus has been solved by multiple isomorphous replacement and refined at 1.5 A resolution. The subunit of the tetrameric molecule of 222 symmetry consists of a single polypeptide chain of about 500 amino acid residues and one haem group.

Crystallization and preliminary X-ray investigation of phosphoribosylaminoimidazolesuccinocarboxamide synthase from the yeast Saccharomyces cerevisiae.

Crystals of phosphoribosylaminoimidazolesuccinocarboxamide synthase (EC 6.3.2.

Comparison of beef liver and Penicillium vitale catalases.

The structures of Penicillium vitale and beef liver catalase have been determined to atomic resolution. Both catalases are tetrameric proteins with deeply buried heme groups. The amino acid sequence of beef liver catalase is known and contains (at least) 506 amino acid residues.

Three-dimensional structure of catalase from Penicillium vitale at 2.0 A resolution.

The three-dimensional structure analysis of crystalline fungal catalase from Penicillium vitale has been extended to 2.0 A resolution. The crystals belong to space group P3(1)21, with the unit cell parameters of a = b = 144.

[Temperature and time stability of proteins in concentrated solutions].

A comparative calorimetric study of temperature stability of proteins in reversible and nonreversible denaturation has been carried out by means of continuous heating of its concentrated solutions. A wide range of heating rates (vh) was used. The dependence of denaturation temperature Td on the total heating time is quite different in cases of reversible (RNase, Ph 4) and nonreversible (catalase, PH 7) denaturation.