Unique Biradical Intermediate in the Mechanism of the Heme Enzyme Chlorite Dismutase.

The heme enzyme chlorite dismutase (Cld) catalyzes O-O bond formation as part of the conversion of the toxic chlorite (ClO ) to chloride (Cl) and molecular oxygen (O). Enzymatic O-O bond formation is rare in nature, and therefore, the reaction mechanism of Cld is of great interest. Microsecond timescale pre-steady-state kinetic experiments employing Cld from (Cld), the natural substrate chlorite, and the model substrate peracetic acid (PAA) reveal the formation of distinct intermediates.

Crystal structure of chlorite dismutase, a detoxifying enzyme producing molecular oxygen.

Chlorite dismutase (Cld) is a key enzyme of perchlorate and chlorate respiration. This heme-based protein reduces the toxic compound chlorite into the innocuous chloride anion in a very efficient way while producing molecular oxygen. A sequence comparison between Cld homologues shows a highly conserved family.

Characterization of a diagnostic Fab fragment binding trimeric Lewis X.

Lewis X trisaccharides normally function as essential cell-cell interaction mediators. However, oligomers of Lewis X trisaccharides expressed by the parasite Schistosoma mansoni seem to be related to its evasion of the immune response of its human host. Here we show that monoclonal antibody 54-5C10-A, which is used to diagnose schistosomiasis in humans, interacts with oligomers of at least three Lewis X trisaccharides, but not with monomeric Lewis X.

Recycling of aborted ribosomal 50S subunit-nascent chain-tRNA complexes by the heat shock protein Hsp15.

When heat shock prematurely dissociates a translating bacterial ribosome, its 50S subunit is prevented from reinitiating protein synthesis by tRNA covalently linked to the unfinished protein chain that remains threaded through the exit tunnel. Hsp15, a highly upregulated bacterial heat shock protein, reactivates such dead-end complexes. Here, we show with cryo-electron microscopy reconstructions and functional assays that Hsp15 translocates the tRNA moiety from the A site to the P site of stalled 50S subunits.

Cloning, expression, purification, crystallization and preliminary X-ray diffraction analysis of chlorite dismutase: a detoxifying enzyme producing molecular oxygen.

Chlorite dismutase, a homotetrameric haem-based protein, is one of the key enzymes of (per)chlorate-reducing bacteria. It is highly active (>2 kU mg(-1)) in reducing the toxic compound chlorite to the innocuous chloride anion and molecular oxygen. Chlorite itself is produced as the intermediate product of (per)chlorate reduction.

Spectroscopic characterization and ligand-binding properties of chlorite dismutase from the chlorate respiring bacterial strain GR-1.

Chlorite dismutase (EC 1.13.11.