Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.17 (lysozyme)
 21,489 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cellosyl is a bacterial muramidase from Streptomyces coelicolor. Similar to other lysozymes, the enzyme cleaves the beta-1,4-glycosidic bond between N-acetylmuramic acid and N-acetylglucosamine units, but it also exhibits a beta-1,4-N,6-O-diacetylmuramidase activity. The latter enables Cellosyl to degrade the cell walls of Staphylococcus aureus, which are not hydrolyzed by chicken-, goose-, or bacteriophage T4-type lysozymes. The enzymatic activity and amino acid sequence of Cellosyl group it with lysozymes of the Chalaropsis type, for which no detailed structural information has been available so far. The crystal structure of Cellosyl from S. coelicolor has been determined to a resolution of 1.65 A and refined to an R-factor of 15.2%. The enzyme is comprised of a single domain and possesses an unusual beta/alpha-barrel fold. The last strand, beta 8, of the (beta/alpha)(5)beta(3)-barrel is found to be antiparallel to strands beta 7 and beta 1. Asp-9, Asp-98, and Glu-100 are located at the active site. The structure of Cellosyl exhibits a new lysozyme fold and represents a new class of polysaccharide-hydrolyzing beta/alpha-barrels.
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PMID:A new lysozyme fold. Crystal structure of the muramidase from Streptomyces coelicolor at 1.65 A resolution. 1142 28

Serum is an environment in which bacterial cells should not exist. The serum complement system provides innate defense against microbial infections. It consists of at least 35 proteins, mostly in pre-activated enzymatic forms. The activation of complement is achieved through three major pathways: the classical, alternative, and lectin. Lysozyme, widely present in body fluids, catalyzes the hydrolysis of beta 1,4 linkage between N-acetyloglucosamine and N-acetylmuramic acid in the bacterial cell wall and cooperates with the complement system in the bactericidal action of serum. In this study, ten strains of serotype O48 Salmonella, mainly associated with warm-blooded vertebrates and clinically important causing diarrhea in infants and children, were tested. The results demonstrated that the most efficient killing of Salmonella O48 occurred when all the components of normal bovine serum (NBS) and normal human serum (NHS) cooperated. To prove the role of lysozyme in the bactericidal activity of bovine and human serum, the method of serum adsorption onto bentonite (montmorillonite, MMT) was used. In order to investigate structural transitions accompanying the adsorption of serum components, we applied X-ray diffraction methods. The results of this investigation suggested that apart from lysozyme, other proteins (as, e.g., C3 protein or IgG immunoglobulin) were adsorbed on MMT particles. It was also shown that Ca(2+) cations can be adsorbed on bentonite. This may explain the different sensitivities of the serovars belonging to the same O48 Salmonella serotype to NBS and NHS devoid of lysozyme.
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PMID:Killing of Gram-negative bacteria with normal human serum and normal bovine serum: use of lysozyme and complement proteins in the death of Salmonella strains O48. 1929 63

Chitin, a homopolymer of N-acetyl-D-glucosamine (GlcNAc) residues linked by beta 1-4 bonds, is the most abundant renewable natural resource after cellulose. It is widely distributed in nature as the integuments of crustaceans and insects and as a component of fungi and algae. This study investigated the effects of a bifunctional chitinase/lysozyme-producing strain, Pseudomonas aeruginosa K-187, on degradation of shrimp shells and the survival conditions of bacterial strains in mangrove river sediment of Tamsui River. The structures of the whole bacterial community of the samples were measured by using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) technique. Results show that three bacterial strains (Acrobacter sp., Shewanella sp., and Marinobacterium sp.) which originated from the mangrove river sediment were found predominant in the 6 days-incubation sample of P. aeruginosa K-187 amended mangrove river sediment. Meanwhile, biomass, reducing sugar, and total sugar were found highest in the 6 weeks-incubation sample of shrimp shell powder and P. aeruginosa K-187-amended mangrove river sediment. According to the results, we assumed that the amendment of P. aeruginosa K-187 can enhance the biodegradation of shrimp shells in the seawater containing mangrove river sediment. We hope that these findings may provide some useful information for the reclamation of chitin-containing wastes in our environment.
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PMID:Biodegradation and microbial community changes upon shrimp shell wastes amended in mangrove river sediment. 2051 38


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