Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: EC:3.2.1.17 (lysozyme)
21,489 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Using molecular approaches, we have recently shown that the C7-10 mosquito cell line from Aedes albopictus, and the Aag-2 line from Aedes aegypti, secrete a variety of immune peptides into the culture medium, including cecropins, defensins, transferrin, and lysozyme. The diversity of these peptides makes it difficult to quantify the relative activities of each molecule, because possible synergistic interactions may occur. Using a microtiter plate assay with live bacteria, we now show that C7-10 cells secrete an activity that is more potent against the Gram-positive bacterium, Micrococcus luteus, than against Gram-negative Escherichia coli. This lysozyme-like activity is accompanied by production of a lytic zone in an agarose plate assay containing commercially available, lyophilized M. luteus. Properties of the lysozyme-like activity from C7-10 cells included a broad pH optimum from 5.5 to 6.5, and heat-sensitivity above 42 degrees C. Amounts of secreted activity increased during the initial 24h of incubation with heat-killed bacteria. During this induction, lysozyme-like activity was found primarily in the cell culture supernatant.
...
PMID:Detection of lysozyme-like enzymatic activity secreted by an immune-responsive mosquito cell line. 1267 52

Sequence of a tick gut lysozyme (TGL) from the soft tick Ornithodoros moubata was determined by cloning and sequencing of overlapping polymerase chain reaction (PCR) and RACE PCR products. It is the first lysozyme sequence representing the subphylum Chelicerata. The resulting open reading frame codes for a putative signal peptide of 22 amino-acid residues and a mature protein composed of 124 amino-acids. Calculated mass of the protein is 14037.75 Da and a theoretical isoelectric point is 8.16. The phylogenetic analysis revealed that the TGL belongs to the c-type lysozymes. It forms a distinct monophyletic group together with multiple lysozyme-like sequences found in the gene products agCP6542 from Anopheles gambiae strain PEST and CG8492-PA from Drosophila melanogaster. This group is referred to as an H-branch due to a unique histidine residue at position 52 which replaces the highly conserved tyrosine present in the vast majority of c-type lysozymes. TGL seems to be an interesting case in which the features of lysozymes with anti-bacterial and digestive function are combined. Semi-quantitative RT-PCR and Northern blotting analysis demonstrated that TGL is strongly up-regulated at the transcriptional level after a bloodmeal. The maximum lysozyme mRNA level was detected 16 h post bloodmeal and the message remained stable for 5 days and then it slowly dropped down to the level of non-fed ticks within 2 weeks.
...
PMID:Lysozyme from the gut of the soft tick Ornithodoros moubata: the sequence, phylogeny and post-feeding regulation. 1279 62

Ralston, Doris J. (University of California, Berkeley), B. S. Baer, and S. S. Elberg. Lysis of brucellae by the combined action of glycine and a lysozyme-like agent from rabbit monocytes. J. Bacteriol. 82:342-353. 1961.-An acid-extractable lytic material was obtained from rabbit monocytes. It acts on a substrate in the walls of brucellae and has properties similar to egg-white lysozyme. Brucella melitensis strain Rev Is is completely resistant to this agent and also to crystalline lysozyme, but when the cells are exposed to sufficient amounts of glycine, the surface is rendered susceptible to these lytic agents. Rough type Rev Is cells are more susceptible than smooth, and the virulent B. melitensis strain 6015 is most resistant.
...
PMID:Lysis of brucellae by the combined action of glycine and a lysozyme-like agent from rabbit monocytes. 1373 76

Bulgecin A, a bacterial metabolite, has been shown to bind in the active-site groove of the chicken-type lysozyme from the rainbow trout (RBTL) and in the lysozyme-like C-terminal domain, of a soluble lytic transglycosylase (C-SLT) from Escherichia coli. These enzymes are muramidases that cleave the glycosidic bonds in the glycan strands of the murein polymer. Here we report the crystal structure of a complex between the goose-type lysozyme from the egg white of the Australian black swan (SEWL) and bulgecin A at 2.45 A resolution. As is the case for the C-SLT/bulgecin and RBTL/bulgecin complexes, the ligand binds with the N-acetylglucosamine ring in subsite C and the proline moiety in site D where it interacts with the catalytic glutamic acid. The taurine residue interacts with the beta-sheet region. Comparisons of the three buigecin complexes show that the inhibitor has the same binding mode to the muramidases with similar protein-ligand interactions, particularly for SEWL and RBTL. From our results, it seems likely that bulgecin, in general, inhibits enzymes with lysozyme-like domains and thus might represent a novel class of natural antibiotics that act on murein-degrading rather than murein-synthesizing enzymes.
...
PMID:Structure of a bulgecin-inhibited g-type lysozyme from the egg white of the Australian black swan. A comparison of the binding of bulgecin to three muramidases. 1529 31

Bulgecin, a sulfonated glycopeptide produced by Pseudomonas acidophila and Pseudomonas mesoacidophila, induces bulge formation and enhances lysis of bacterial cell walls when used in combination with beta-lactam antibiotics. The compound does not itself exhibit any antibacterial activity, but has been shown to inhibit a soluble lytic transglycosylase (SLT70) from Escherichia coli which has a lysozyme-like domain. Recently, the crystal structure of an SLT-bulgecin complex has been determined to 3.5 A resolution. We report here the crystal structure of a complex between lysozyme from the rainbow trout (RBTL) and bulgecin A at 2.0 A resolution. As for the SLT-bulgecin complex, bulgecin is bound with the glycosaminyl moiety in subsite C and the proline residue in site D of the active-site cleft of RBTL, where it makes hydrogen-bonding interactions with the catalytic residues. The taurine moiety is bound to the left side of subsites E and F in the lower part of the active-site cleft. From the observed position of the bulgecin molecule, it seems reasonable that it is an inhibitor of rainbow trout lysozyme. The lysozymes may, in general, be a target for the design of a novel type of antibiotics distinct from the beta-lactams which are insensitive to the muramidases.
...
PMID:Structure of a complex between bulgecin, a bacterial metabolite, and lysozyme from the rainbow trout. 1529 32

Lysozymes are bacteria-degrading enzymes and play a major role in the immune defense of animals. In free-living protozoa, lysozyme-like proteins are involved in the digestion of phagocytosed bacteria. Here, we purified a protein with lysozyme activity from Dictyostelium amoebae, which constitutes the founding member, a novel class of lysozymes. By tagging the protein with green fluorescent protein or the Myc epitope, a new type of lysozyme-containing vesicle was identified that was devoid of other known lysosomal enzymes. The most highly expressed isoform, encoded by the alyA gene, was knocked out by homologous recombination. The mutant cells had greatly reduced enzymatic activity and grew inefficiently when bacteria were the sole food source. Over time the mutant gained the ability to internalize bacteria more efficiently, so that the defect in digestion was compensated by increased uptake of food particles.
...
PMID:A Dictyostelium mutant with reduced lysozyme levels compensates by increased phagocytic activity. 1564 Jan 46

Lysozymes, especially c-type lysozymes, are well-recognized bacteriolytic factors widely distributed in the animal kingdom and play a mainly protective role in host defense. The relatives of c-type lysozymes, alpha-lactalbumins, however, are only found in mammalian milk and possess a distinct biological function. These two proteins, having similar amino acid sequences, gene structure, and dimensional conformation, belong to the c-type lysozyme/alpha-lactalbumin family. Using human lysozyme as an information probe, we cloned four human cDNAs encoding homologues of human lysozyme; these were named LYZL2, LYZL4, LYZL6, and SPACA3 by the HUGO Gene Nomenclature Committee. Of these four, SPACA3 has been reported to code an intra-acrosomal sperm protein SLLP1. To our knowledge, the other three are reported here for the first time. Using Northern blot hybridization, including 16 different human tissues, we found that these four lysozyme-like genes were all highly expressed in the testis/epididymis. Further analysis of one, LYZL4, by in situ hybridization revealed that its mRNA was only detected in the epithelium of human epididymis, most abundantly in the caput, suggesting that LYZL4 plays a physiological role in male reproduction. By sequence analysis, we found that two essential catalytic residues of the human lysozyme were conserved in LYZL2 and LYZL6, whereas one site in LYZL4 and two sites in SPACA3 were replaced. The LYZL2, LYZL4, LYZL6, and SPACA3 genes were mapped to human chromosome 10p11.23, 3p21.33, 17q11.2, and 17q12, respectively, and displayed a similar genomic structure. Our data suggest that these four lysozyme-like genes, which have arisen from a common progenitor gene, play a major role in human reproduction.
...
PMID:Molecular cloning and characterization of three novel lysozyme-like genes, predominantly expressed in the male reproductive system of humans, belonging to the c-type lysozyme/alpha-lactalbumin family. 1601 14

Seven new c-type lysozyme genes were found using the Anopheles gambiae genome sequence, increasing to eight the total number of genes in this family identified in this species. The eight lysozymes in An. gambiae have considerable variation in gene structure and expression patterns. Lys c-6 has the most unusual primary amino acid structure as the predicted protein consists of five lysozyme-like domains. Transcript abundance of each c-type lysozyme was determined by semiquantitative RT-PCR. Lys c-1, c-6 and c-7 are expressed constitutively in all developmental stages from egg to adult. Lys c-2 and c-4 also are found in all stages, but with relatively much higher levels in adults. Conversely, Lys c-3 and c-8 transcripts are highest in larvae. Lys c-1, c-6 and c-7 transcripts are found in nearly all the adult tissue samples examined while Lys c-2 and Lys c-4 are more restricted in their expression. Lys c-1 and c-2 transcripts are clearly immune responsive and are increased significantly 6-12 h post challenge with bacteria. The functional adaptive changes that may have evolved during the expansion of this gene family are briefly discussed in terms of the expression patterns, gene and protein structures.
...
PMID:Characterization of the c-type lysozyme gene family in Anopheles gambiae. 1613 42

We have identified two new lysozyme-like protein families by using a combination of sequence similarity searches, domain architecture analysis, and structural predictions. First, the P5 protein from bacteriophage phi8, which belongs to COG3926 and Pfam family DUF847, is predicted to have a new lysozyme-like domain. This assignment is consistent with the lytic function of P5 proteins observed in several related double-stranded RNA bacteriophages. Domain architecture analysis reveals two lysozyme-associated transmembrane modules (LATM1 and LATM2) in a few COG3926/DUF847 members. LATM2 is also present in two proteins containing a peptidoglycan binding domain (PGB) and an N-terminal region that corresponds to COG5526 with uncharacterized function. Second, structure prediction and sequence analysis suggest that COG5526 represents another new lysozyme-like family. Our analysis offers fold and active-site assignments for COG3926/DUF847 and COG5526. The predicted enzymatic activity is consistent with an experimental study on the zliS gene product from Zymomonas mobilis, suggesting that bacterial COG3926/DUF847 members might be activators of macromolecular secretion.
...
PMID:COG3926 and COG5526: a tale of two new lysozyme-like protein families. 1615 6

The culturability of several actinobacteria is controlled by resuscitation-promoting factors (Rpfs). These are proteins containing a c. 70-residue domain that adopts a lysozyme-like fold. The invariant catalytic glutamate residue found in lysozyme and various bacterial lytic transglycosylases is also conserved in the Rpf proteins. Rpf from Micrococcus luteus, the founder member of this protein family, is indeed a muralytic enzyme, as revealed by its activity in zymograms containing M. luteus cell walls and its ability to (i) cause lysis of Escherichia coli when expressed and secreted into the periplasm; (ii) release fluorescent material from fluorescamine-labelled cell walls of M. luteus; and (iii) hydrolyse the artificial lysozyme substrate, 4-methylumbelliferyl-beta-D-N,N',N''-triacetylchitotrioside. Rpf activity was reduced but not completely abolished when the invariant glutamate residue was altered. Moreover, none of the other acidic residues in the Rpf domain was absolutely required for muralytic activity. Replacement of one or both of the cysteine residues that probably form a disulphide bridge within Rpf impaired but did not completely abolish muralytic activity. The muralytic activities of the Rpf mutants were correlated with their abilities to stimulate bacterial culturability and resuscitation, consistent with the view that the biological activity of Rpf results directly or indirectly from its ability to cleave bonds in bacterial peptidoglycan.
...
PMID:Muralytic activity of Micrococcus luteus Rpf and its relationship to physiological activity in promoting bacterial growth and resuscitation. 1635 20


<< Previous 1 2 3 4 5 6 Next >>

---