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)

The genes required for gamma-polyglutamic acid (PGA) production were cloned from Bacillus subtilis IFO16449, a strain isolated from fermented soybeans. There were four open reading frames in the cloned 4.2-kb DNA fragment, and they were almost identical to those in the ywsC and ywtABC genes of B. subtlis 168. Northern blot analysis showed that the four genes constitute an operon. Three genes, ywsC, ywtA, and ywtB, were disrupted to determine which gene plays a central role in PGA biosynthesis. No PGA was produced in Delta ywsC and Delta ywtA strains, indicating that both of these genes are essential for PGA production. To clarify the function of the YwsC protein, histidine-tagged YwsC (YwsC-His) was produced in the Delta ywsC strain and purified from the lysozyme-treated lysate of the transformant by Ni-nitrilotriacetic acid affinity chromatography. Western blot analysis revealed that the YwsC-His protein consists of two subunits, the 44-kDa and 33-kDa proteins, which are encoded by in-phase overlapping in the ywsC gene. (14)C-labeled PGA was synthesized by the purified proteins from L-[(14)C]-glutamate in the presence of ATP and MnCl(2), through an acylphosphate intermediate, indicating that the ywsC gene encodes PGA synthetase (EC 6.3.2), a crucial enzyme in PGA biosynthesis.
...
PMID:Characterization of the Bacillus subtilis ywsC gene, involved in gamma-polyglutamic acid production. 1175 9

The complete amino acid sequence of cassowary (Casuarius casuarius) goose type lysozyme was analyzed by direct protein sequencing of peptides obtained by cleavage with trypsin, V8 protease, chymotrypsin, lysyl endopeptidase, and cyanogen bromide. The N-terminal residue of the enzyme was deduced to be a pyroglutamate group by analysis with a LC/MS/MS system equipped with the oMALDI ionization source, and then confirmed by a glutamate aminopeptidase enzyme. The blocked N-terminal is the first reported in this enzyme group. The positions of disulfide bonds in this enzyme were chemically identified as Cys4-Cys60 and Cys18-Cys29. Cassowary lysozyme was proved to consist of 185 amino acid residues and had a molecular mass of 20408 Da calculated from the amino acid sequence. The amino acid sequence of cassowary lysozyme compared to that of reported G-type lysozymes had identities of 90%, 83%, and 81%, for ostrich, goose, and black swan lysozymes, respectively. The amino acid substitutions at PyroGlu1, Glu19, Gly40, Asp82, Thr102, Thr156, and Asn167 were newly detected in this enzyme group. The substituted amino acids that might contribute to substrate binding were found at subsite B (Asn122Ser, Phe123Met). The amino acid sequences that formed three alpha-helices and three beta-sheets were completely conserved. The disulfide bond locations and catalytic amino acid were also strictly conserved. The conservation of the three alpha-helices structures and the location of disulfide bonds were considered to be important for the formation of the hydrophobic core structure of the catalytic site and for maintaining a similar three-dimensional structure in this enzyme group.
...
PMID:The primary structure of cassowary (Casuarius casuarius) goose type lysozyme. 1186 97

Atomic solvation parameters (ASPs) are widely used to estimate the solvation contribution to the thermodynamic stability of proteins as well as the free energy of association for protein-ligand complexes. In view of discrepancies in the results of free energies of solvation of folding for various proteins obtained using different atomic solvation parameter sets, systematic studies have been carried out for the calculation of accessible surface area and the changes in free energy of solvation of folding (deltaG(s,f)) for mutants of lysozyme T4 where threonine 157 is replaced by amino acids: cysteine, aspartate, glutamate, phenylalanine, glycine, histidine, isoleucine, leucine, asparagine, arginine, serine and valine. The deviations of the calculated results from the experimental results are discussed to highlight the discrepancies in the atomic solvation parameter sets and possible reasons for them. The results are also discussed to throw light on the effect of chain free energy and hydrogen bonding on the stability of mutants. The octanol to water-based ASP sets 'Sch1' and 'EM' perform better than the vacuum to water-based ASP sets. The vacuum to water-based ASP sets 'Sch3' and 'WE' can be used to predict the stability of mutants if a proper method to calculate the hydrogen bond contribution to overall stability is in place.
...
PMID:Theoretical studies on solvation contribution to the thermodynamic stability of mutants of lysozyme T4. 1287 74

The role of glutamate as osmoprotector was investigated through the study of a mutation in its biosynthetic pathway. A glt::Tn917-lacZ-cat insertion mutant (N1) conferring glutamate auxotrophy and enhanced beta-galactosidase expression on high-salt media was selected. Co-transformation experiments and PCR analysis allowed locating the insertion into the gltB gene corresponding to the small unit of the glutamate synthase (GOGAT). The N1 mutant strain presented a glutamate requirement for growth and a tenfold decrease in GOGAT activity. Transcriptional activity of GOGAT, measured as beta-galactosidase from the transposon fusion, correlated with enzymatic activity; expression was enhanced at the stationary phase and in high-ionic-strength media. However, osmotolerance of cultures of N1 mutant were as wild-type (wt), at least in semi-rich medium. In contrast, sporulation was slightly reduced (75% of wt), and spores were less resistant to UV, heat, and osmolarity, properties linked to the content of small, acid-soluble proteins (SASP). The content of these proteins was, in fact, reduced, in particular the SASP-gamma type. The peptidoglycan-cortex, however, was not impaired since spores maintained lysozyme resistance. Addition of glutamate during sporulation partially rescued spore resistance, but germination and outgrowth remained impaired. Deficiencies in germination and outgrowth were also observed with spores from a gltA mutant strain. Taken together, these results pointed to the importance of GOGAT activity during sporulation, in particular for the synthesis SASPs.
...
PMID:Effect of glutamate synthase (GOGAT) activity on Bacillus subtilis spore properties. 1457 Feb 71

A group B streptococcal (GBS) bacteriophage lysin gene was cloned and expressed in Escherichia coli. The purified recombinant enzyme, calculated to have a molecular mass of 49 677 Da, lysed GBS cells. The susceptibility of GBS cells to lysis by the enzyme depended upon the growth stage at which they were harvested, with early exponential phase cells most sensitive. Calcium ions enhanced the activity of the enzyme. The enzyme also lysed other beta-haemolytic streptococci, including groups A, C, E and G streptococci, but not common oral streptococci, including Streptococcus mutans. The generation of both reducing activity and N-terminal alanine residues during lysis indicated that the lysin is a bifunctional enzyme, possessing both glycosidase and endopeptidase activities. This is consistent with the presence of two conserved sequence domains, an Acm (acetylmuramidase) domain associated with lysozyme activity, and a CHAP (cysteine, histidine-dependent amidohydrolases/peptidases) domain associated with endopeptidase activity. Site-directed mutagenesis of conserved cysteine and histidine residues in the CHAP domain and conserved aspartate and glutamate residues in the Acm domain confirmed their importance for lysozyme and endopeptidase activity respectively.
...
PMID:The bifunctional peptidoglycan lysin of Streptococcus agalactiae bacteriophage B30. 1525 51

Bundles of F-actin and DNA present in the sputum of cystic fibrosis (CF) patients but absent from normal airway fluid contribute to the altered viscoelastic properties of sputum that inhibit clearance of infected airway fluid and exacerbate the pathology of CF. Previous strategies to remove these filamentous aggregates have focused on DNase to enzymatically depolymerize DNA to constituent monomers and gelsolin to sever F-actin to small fragments. The high densities of negative surface charge on DNA and F-actin suggest that the bundles of these filaments, which alone exhibit a strong electrostatic repulsion, may be stabilized by multivalent cations such as histones, antimicrobial peptides, and other positively charged molecules prevalent in airway fluid. This study reports that bundles of DNA or F-actin formed after addition of histone H1 or lysozyme are efficiently dissolved by soluble multivalent anions such as polymeric aspartate or glutamate. Addition of poly-aspartate or poly-glutamate also disperses DNA and actin-containing bundles in CF sputum and lowers the elastic moduli of these samples to levels comparable to those obtained after treatment with DNase I or gelsolin. Addition of poly-aspartic acid also increased DNase activity when added to samples containing DNA bundles formed with histone H1. When added to CF sputum, poly-aspartic acid significantly reduced the growth of bacteria, suggesting activation of endogenous antibacterial factors. These findings suggest that soluble multivalent anions have potential alone or in combination with other mucolytic agents to selectively dissociate the large bundles of charged biopolymers that form in CF sputum.
...
PMID:Anionic poly(amino acid)s dissolve F-actin and DNA bundles, enhance DNase activity, and reduce the viscosity of cystic fibrosis sputum. 1596 1

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

Antibacterial proteins like lysozyme are important components of the insect non-specific immune response against bacteria. The complementary deoxyribonucleic acid (cDNA) encoding a new lysozyme from Triatoma infestans, named lysozyme2, has been amplified by polymerase chain reaction and the rapid amplification of cDNA ends technique. The gene is expressed in the small intestine of the insect. The deduced protein sequence shows up to 70% similarity to lysozymes from other species. Furthermore, the protein exhibits significant structural concordance to other insect lysozymes. A striking feature of the lysozyme2 protein is the replacement of the conserved amino acid residues of the active site of classical c-type lysozymes, glutamate and aspartate, by valine and tyrosine.
...
PMID:Sequence characterization of an unusual lysozyme gene expressed in the intestinal tract of the reduviid bug Triatoma infestans (Insecta). 1789 95

The peptidoglycan glycosyltransferase (GT) module of class A penicillin-binding proteins (PBPs) and monofunctional GTs catalyze glycan chain elongation of the bacterial cell wall. These enzymes belong to the GT51 family, are characterized by five conserved motifs, and have some fold similarity with the phage lambda lysozyme. In this work, we have systematically modified all the conserved amino acid residues of the GT module of Escherichia coli class A PBP1b by site-directed mutagenesis and determined their importance for the in vivo and in vitro activity and the thermostability of the protein. To get an insight into the GT active site of this paradigm enzyme, a model of PBP1b GT domain was constructed based on the available crystal structures (PDB codes 2OLV and 2OLU). The data show that in addition to the essential glutamate residues Glu233 of motif 1 and Glu290 of motif 3, the residues Phe237 and His240 of motif 1 and Gly264, Thr267, Gln271, and Lys274 of motif 2, all located in the catalytic cavity of the GT domain, are essential for the in vitro enzymatic activity of the PBP1b and for its in vivo functioning. Thus, the first three conserved motifs contain most of the residues that are required for the GT activity of the PBP1b. The residues Asp234, Phe237, His240, Thr267, and Gln271 are proposed to maintain the structure of the active site and the positioning of the catalytic Glu233.
...
PMID:Importance of the conserved residues in the peptidoglycan glycosyltransferase module of the class A penicillin-binding protein 1b of Escherichia coli. 1870 63

Glucocorticoids play a role in the origin of the features of the metabolic diseases. Alpha-ketoglutarate (AKG) is defined as glutamine homologue and derivative, conditionally an essential amino acid. In the liver, glutamine serves as a precursor for ureagenesis, gluconeogenesis and acute phase protein synthesis The aim of the study was to determine the effect of AKG administered to piglets prenatally exposed to dexamethasone, on the structure of the liver and its metabolic function. Sows were administered with dexamethasone (3 mg/sow/48 h) from day 70 of pregnancy to the parturition, and then after the birth, the piglets were divided into the group administered with AKG (0.4 g/kg body weight) or physiological saline. Biochemical markers, lysozyme and ceruloplasmin serum activities, concentrations of selected free amino acids, macro- and microelements and histomorphometry of the liver tissue were determined. The total cholesterol concentrations in the sows and their newborns from the Dex groups were higher by 72% and 64%, respectively, compared with the control groups. Triacylglycerol concentration was higher by 50% in sows from the Dex group and 55% in the new-born piglets. Alpha-ketoglutarate administered to the piglets after prenatal influence of dexamethasone lowered the total cholesterol concentration by 40%, and enhanced aspartate by 41%, serine by 76%, glutamate by 105%, glutamine by 36%, glycine by 53% and arginine by 105%, as well as methionine and cystathionine, but increased the sulphur concentration compared with the control (p < 0.01). Intracellular space D decreased after AKG administration in comparison with the piglets from Dex/Control group not treated with AKG. Postnatal administration of AKG had a protective effect on liver structure, and lowered the total cholesterol concentration in piglets prenatally exposed to dexamethasone, and also influenced selected macro- and microelement serum concentrations and amino acids plasma concentration.
...
PMID:Alpha-ketoglutarate protects the liver of piglets exposed during prenatal life to chronic excess of dexamethasone from metabolic and structural changes. 1932 Sep 32


<< Previous 1 2 3 4 5 6 7 Next >>

---