Olga A Stepnaya

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Although bacteriophage T5 is known to have lytic proteins for cell wall hydrolysis and phage progeny escape, their activities are still unknown. This is the first report on the cloning, expression and biochemical characterization of a bacteriophage T5 lytic hydrolase. The endolysin-encoding lys gene of virulent coliphage T5 was cloned in Escherichia coli(More)
Membrane vesicles produced by bacteria have been intensively studied in the recent years. Investigators have noted their roles in essential processes in the bacterial cell including secretion of proteins by the 'eukaryotic' vesicular mechanism. To date, formation of vesicles is not considered to be a spontaneous event. Many believe it to be a programmed(More)
The Gram-negative bacterium Lysobacter sp. XL1 secretes lytic enzymes (L1-L5) into the culture medium. Enzyme L5 is the most recently found extracellular lytic enzyme of this bacterium. The paper presents the results of the isolation and characterization of some properties of this enzyme. Thus, enzyme L5 of Lysobacter sp. XL1 is a lytic serine protease.(More)
The N-terminal amino acid sequence (23 amino acid residues) and the amino acid composition of the extracellular bacteriolytic enzyme L1 of 21 kD from the bacterium Lysobacter sp. XL1 have been determined. The enzyme was hydrolyzed by trypsin, the resulting peptides were isolated, and their primary structures were determined. A high extent of homology (92%-)(More)
139 The gram-negative bacterium Lysobacter sp. cultured in a specially selected medium secretes hydrolytic enzymes into the medium. Five of these enzymes (L1–L5), which have a lytic effect on various microorganisms, are of special interest [1–6]. By the specificity of effect on bacterial peptideglycanes, three of them (L1, L4, and L5) are classified into(More)
The structure of an acidic polysaccharide component of a bacteriolytic complex (lysoamidase), isolated from a bacterium of the genus Xanthomonas, was studied. On the basis of sugar analysis and one- and two-dimensional 1H and 13C NMR spectroscopic study of the initial polysaccharide and its O-deacetylated and carboxyl-reduced derivatives, the following(More)
The Gram-negative bacterium Lysobacter sp. XL1 secretes various proteins, including bacteriolytic enzymes (L1-L5), into the culture medium. These proteins are able to degrade Gram-positive bacteria. The mechanism of secretion of extracellular proteins by Lysobacter sp. XL1 has not been studied hitherto. Electron microscopic investigations revealed the(More)
Lytic enzymes are the group of hydrolases that break down structural polymers of the cell walls of various microorganisms. In this work, we determined the nucleotide sequences of the Lysobacter sp. strain XL1 alpA and alpB genes, which code for, respectively, secreted lytic endopeptidases L1 (AlpA) and L5 (AlpB). In silico analysis of their amino acid(More)
The effect of the extracellular bacteriolytic enzymes of Lysobacter sp. on gram-negative bacteria was studied. These enzymes were found to be able to hydrolyze the peptidoglycan that was isolated from the gram-negative bacteria, the hydrolysis being completely inhibited by the cell wall lipopolysaccharide of these bacteria. The native cells of the(More)
A system of intracellular peptidoglycan hydrolases of Xanthomonas campestris XL-1 comprises about 10 enzymes of different localization and substrate specificity. Seven enzymes (A1-A7) are localized in cytosol, one enzyme (A8) in periplasm, and two enzymes (A9, A10) were found in the fraction of cell walls and membranes. While the culture is entering the(More)