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PubMed1970

The cell wall of Bacillus licheniformis N.C.T.C. 6346. Linkage between the teichuronic acid and mucopeptide components.

1. After extraction of teichoic acid from cell walls of Bacillus licheniformis with dilute alkali, the insoluble residue contains the teichuronic acid and mucopeptide components and a small amount of residual phosphorus. 2. A complex of teichuronic acid and a part of the mucopeptide was isolated from the soluble fraction obtained by lysozyme treatment of alkali extracted walls. 3. Small-molecular-weight mucopeptide fragments, not containing teichuronic acid, are obtained from the soluble fraction in yields similar to those obtained after treatment of whole walls or acid-extracted walls with lysozyme. 4. The covalent linkages between teichuronic acid and mucopeptide are broken by treatment with dilute acid. The release of teichuronic acid chains is accompanied by the hydrolysis of N-acetylgalactosaminide linkages and the exposed N-acetylgalactosamine residues form chromogen under very mild conditions, indicating that they are substituted on C-3. 5. The initial rate of formation of reactive N-acetylgalactosamine residues during mild acid hydrolysis is parallel to the rate of extraction under the same conditions of teichuronic acid from alkali-treated insoluble walls, and to the rate of acid hydrolysis of glucose 1-phosphate. 6. The results suggest that the teichuronic acid chains are attached through reducing terminals of N-acetylgalactosamine residues to phosphate groups in the mucopeptide. 7. Muramic acid phosphate was isolated from the insoluble mucopeptide remaining after extraction of walls with dilute alkali followed by dilute acid.

Bacillus↗
PubMed1985

Characterization of a novel linkage unit between ribitol teichoic acid and peptidoglycan in Listeria monocytogenes cell walls.

The structure of the linkage unit between ribitol teichoic acid and peptidoglycan in the cell walls of Listeria monocytogenes EGD was studied. A teichoic-acid--glycopeptide preparation isolated from lysozyme digests of the cell walls of this strain contained mannosamine, glycerol, glucose and muramic acid 6-phosphate in an approximate molar ratio of 1:1:2:1, together with large amounts of glucosamine and other components of teichoic acid and glycopeptides. A teichoic-acid-linked sugar preparation, obtained by heating the cell walls at pH 2.5, also contained glucosamine, mannosamine, glycerol and glucose in an approximate molar ratio of 25:1:1:2. Part of the glucosamine residues were shown to be involved in the linkage unit. Thus, on mild alkaline hydrolysis, the teichoic-acid-linked sugar preparation gave a disaccharide characterized as N-acetylmannosaminyl(beta 1----4)-N-acetylglucosamine [ManNAc(beta 1----4)GlcNAc] in addition to the ribitol teichoic acid moiety, whereas the teichoic-acid - glycopeptide was separated into disaccharide-linked glycopeptide and the ribitol teichoic acid moiety by the same procedure. Furthermore, Smith degradation of the cell walls gave a characteristic fragment, EtO2-P-Glc(beta 1----3)Glc(beta 1----1/3)Gro-P-ManNAc(beta 1----4)GlcNAc (where EtO2 = 1,2-ethylenediol and Gro = glycerol). The results lead to the conclusion that in the cell walls of this organism, the ribitol teichoic acid chain is linked to peptidoglycan through a novel linkage unit, Glc(beta 1----3)Glc(beta 1----1/3)Gro-P-(3/4)ManNAc-(beta 1----4)GlcNAc.

Cell Wall↗
PubMed1985

Activation of mouse peritoneal adherent cells with N-acyl muramyl dipeptide derivatives.

The effect of N-acyl derivatives of muramyl dipeptide (N-acetyl muramyl-L-alanyl-D-isoglutamine) on the activation of peritoneal adherent cells (PAC) in vivo and on the stimulation of nonspecific host resistance against Escherichia coli infection was examined in comparison with the effect of 6-O-stearoyl muramyl dipeptide. N-acyl muramyl dipeptide derivatives increased the release of hydrogen peroxide (H2O2) by PAC from mice treated 1 day before upon stimulation with phorbol myristate acetate, and their activities did not depend on the chain length or kinds of fatty acids introduced. The results obtained using N-stearoyl muramyl dipeptide analogs indicated that the acyl moiety combined to muramic acid played a more important role in the ability of PAC to release H2O2 than did the peptide moiety. PAC from mice treated with N-stearoyl muramyl dipeptide, N-(3-hydroxy-2-docosylhexacosanoyl) muramyl dipeptide, and 6-O-stearoyl muramyl dipeptide 1 day before, including 20 to 42% polymorphonuclear leukocytes, released large amount of H2O2, and most of the H2O2 released was due to the attribution of polymorphonuclear leukocytes. The cytostatic activity of PAC from mice treated with these three compounds reached a maximum on day 3 after injection, and the cytolytic activity of PAC was induced by N-stearoyl muramyl dipeptide on day 3 and by 6-O-stearoyl muramyl dipeptide on day 1 after injection. In contrast to the above results, N-acyl muramyl dipeptide derivatives did not stimulate nonspecific host resistance against E. coli infection in mice when compared to 6-O-stearoyl muramyl dipeptide.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1987

[Polysaccharide composition of the cell wall of Streptomyces antibioticus RIA-594(39), a producer of the antibiotic oleandomycin].

The main polysaccharide components of the cell wall in S. antibioticus RIA-594 (39) i.e. peptidoglycan, teichoic acid and polysaccharide were studied. Peptidoglycan consists of the polysaccharide fraction containing equimolar quantities of N-acetylglucosamine and muramic acid and the peptide subunits including alanine, glutamic and L,L-diaminopimelic acids and glycine at a ratio of 1.4:0.9:1:0.9. It is characteristic that certain peptide subunits of the streptomycete contain no alanine. A polysaccharide differing from glycerol teichoic acid and containing galactose and N-acetylglucosamine was isolated from the cell wall. During the streptomycete development the quantity of peptidoglycan remained constant, the quantity of teichoic acid lowered and the quantity of polysaccharide increased. Correlation between the presence of aminosugars in the composition of teichoic acid and polysaccharide specific of the streptomycete cell wall and the presence of aminosugars in the structure of oleandomycin was shown. This is probably connected with characteristic features of the organism physiology.

Amino Acids↗
PubMed1965

THE INCORPORATION OF LABELLED AMINO SUGARS BY BACILLUS SUBTILIS.

1. N-Acetyl[1-(14)C]glucosamine (10mum-5mm) is incorporated by cells of Bacillus subtilis at a constant rate (0.2-2mmumoles/mg. dry wt./hr.). The rate of [1-(14)C]glucosamine (2.5mum-5mm) incorporation is proportional to the concentration; it approaches that of N-acetyl[1-(14)C]glucosamine at 5mm. 2. Label from N-acetyl-[1-(14)C]glucosamine and [1-(14)C]glucosamine is incorporated predominantly into the ;hot-trichloroacetic acid-soluble' and ;residue' fractions of cells. Acid hydrolysis of the hot-trichloroacetic acid-soluble fraction yields mainly [(14)C]glucosamine; hydrolysis of the residue fraction yields [(14)C]glucosamine and [(14)C]muramic acid. The label from N-[1-(14)C]acetylglucosamine and sodium [1-(14)C]acetate enters most cell fractions. Incorporation of N-[1-(14)C]acetylglucosamine is inhibited by the addition of unlabelled acetate. 3. Glucose competes with [1-(14)C]glucosamine for incorporation. N-Propionylglucosamine and N-formylglucosamine compete with N-acetyl[1-(14)C]glucosamine. 4. Cells pregrown on N-acetylglucosamine or glucosamine incorporate up to ten times as much N-acetyl[1-(14)C]glucosamine or [1-(14)C]glucosamine in a given time as cells pregrown on glucose.

Acetates↗
PubMed1970

Bacteriolytic enzymes from Staphylococcus aureus. Specificity of ction of endo-beta-N-acetylglucosaminidase.

The bacteriolytic enzyme with an isoelectric point of 9.5 that is produced by all strains of Staphylococcus aureus investigated was purified from strain M18 (Wadström & Hisatsune, 1970). This enzyme released reducing groups from cell walls of Micrococcus lysodeikticus and was thus shown to be a bacteriolytic hexosaminidase. Although dinitrophenylation and acid hydrolysis of cell walls hydrolysed by a partially purified enzyme gave DNP-alanine and DNP-glycine from staphylococcal peptidoglycan, which indicated the presence of a peptidase and probably also an N-acetylmuramyl-l-alanine amidase, hydrolysis of cell walls by the extensively purified enzyme did not give any DNP-amino acids. The enzyme digest was purified by Amberlite CG-120 and Sephadex G-10 chromatography. Reduction by sodium borohydride of the disaccharide obtained was followed by acid hydrolysis and paper chromatography. Glucosamine completely disappeared after this treatment and a new spot identical with glucosaminitol appeared. The muramic acid spot remained unchanged. The purified enzyme was found to be devoid of exo-beta-N-acetylglucosaminidase activity. These results are compatible with the action of a bacteriolytic endo-beta-N-acetylglucosaminidase. It is also proposed that this enzyme is probably identical with the staphylococcal lysozyme. The mode of action of this has not previously been investigated.

Alanine↗
PubMed1970

Autolysis of isolated cell walls of Bacillus licheniformis N.C.T.C. 6346 and Bacillus subtilis Marburg Strain 168. Separation of the products and characterization of the mucopeptide fragments.

1. Cell walls were isolated from Bacillus licheniformis N.C.T.C. 6346 and Bacillus subtilis Marburg strain 168 trp grown on casein hydrolysate into exponential phase. Autolysis was carried out and the soluble products, separated by chromatography on DEAE-cellulose, from the two wall preparations are broadly similar in composition and are in agreement with autolysis proceeding with hydrolysis of amide bonds between l-alanine and N-acetylmuramic acid residues in the mucopeptide components. 2. Peptides originating from the mucopeptide components were isolated and shown to be a monomer peptide, l-alanyl-d-glutamyl-meso-diaminopimelic acid and a dimer peptide containing two monomer peptides linked through a residue of d-alanine. Approximately one amide group is present for each equivalent tripeptide unit and is probably substituted on diaminopimelic acid residues. 3. Oligosaccharides originating from the mucopeptide components were isolated and after hydrolysis contained almost equimolar amounts of glucosamine and muramic acid and only very small amounts of amino acids. The number-average chain length, estimated by the release of non-reducing end groups of N-acetylglucosamine with exo-beta-N-acetylglucosaminidase, is approximately ten hexosamine residues for oligosaccharides isolated from either organism. The oligosaccharides are polydisperse. 4. N-Acetylglucosamine residues are the only reducing terminals detectable in the oligosaccharides isolated from B. subtilis or B. licheniformis cell-wall autolysates. The number-average chain lengths of the oligosaccharides were determined by estimation of the content of these residues and are higher than those found by enzymic assay. Possible reasons for the discrepancy are discussed.

Autolysis↗
PubMedDate not supplied

Chemosensory responses of Acanthamoeba castellanii: visual analysis of random movement and responses to chemical signals.

A visual assay slide chamber was used in conjunction with time-lapse videomicroscopy to analyze chemotactic behavior of axenically grown Acanthamoeba castellanii. Data were collected and analyzed as vector scatter diagrams and cell tracks. Amebas responded to a variety of bacterial products or potential bacterial products by moving actively toward the attractant. Responses to the chemotactic peptide formyl-methionyl-leucyl-phenylalanine (fMLP), lipopolysaccharide, and lipid A were statistically significant (P < or = 0.03), as was the response to fMLP benzylamide (P < or = 0.05). Significant responses to cyclic AMP, lipoteichoic acid, and N-acetyl glucosamine were also found. Chemotactic peptide antagonists, mannose, mannosylated bovine serum albumin, and N-acetyl muramic acid all yielded nonsignificant responses (P > 0.05). There was no single optimal concentration for response to any of the attractants tested, and amebas responded equally over the range of concentrations tested. Pretreatment of amebas with chemotactic peptides, bacterial products, and bacteria reduced the directional response to attractants. Amebas that had been grown in the presence of bacteria appeared more responsive to chemotactic peptides. Treatment of amebas with trypsin reduced the response of cells to chemotactic peptides, though sensitivity was restored within a couple of hours. This suggests the ameba membrane may have receptors, sensitive to these bacterial substances, which are different from the mannose receptors involved in binding bacteria to the membrane during phagocytosis. The rate of movement was relatively constant (ca. 0.40 microns/s), indicating that the locomotor response to these signals is a taxis, or possibly a klinokinesis, but not an orthokinesis. Studies of the population diffusion rate in the absence of signals indicate that the basic population motility follows the pattern of a Levy walk, rather than the more familiar Gaussian diffusion. This suggests that the usual mathematical models of ameboid dispersion may need to be modified.

Acanthamoeba↗
PubMed1972

Composition of fatty acids and carbohydrates in Leptospira.

The fatty acid and monosaccharide composition of four pathogenic and two saprophytic strains of Leptospira was analyzed by gas chromatography (GC) and GC-mass spectrometry. Among the fatty acids, palmitic acid was most abundant and constituted 30 to 50% of the total fatty acids. Even-numbered unsaturated acids including octadecenoic, hexadecenoic, octadecadienoic, and tetradecadienoic acids comprised 40 to 60% of the total fatty acids. Tetradecanoic acid was about 5% in saprophytic strains, but 1% or less in pathogenic strains. The amount of chloroform-methanol extract of L. biflexa strain Ancona was 14 to 20% of the dry weight of the cell. Tetradecadienoic acid was found in the chloroform-methanol insoluble fraction, suggesting the presence of the acid in a bound form. GC analysis of monosaccharides revealed the existence of arabinose, xylose, rhamnose, mannose, galactose, glucose, glucosamine, and muramic acid in the cells. Among the neutral sugars, glucose was a minor component and was especially low in pathogenic strains. Total pentose content was about two to three times greater than total hexose.

Amino Sugars↗
PubMed1975

Novel type of murein transglycosylase in Escherichia coli.

The purification and properties of a novel type of murein transglycosylase from Escherichia coli are described. The purified enzyme appears as a single band on sodium dodecyl sulfate-polyacrylamide gels and has an apparent molecular weight of approximately 65,000 as estimated by gel filtration and gel electrophoresis. It degrades pure murein sacculi from E. coli almost completely into low-molecular-weight products. The two prominent muropeptide fragments in the digest are the disaccharide-tripeptide N-acetylglucosamine-N-acetylmuramic acid-L-alanine-D-iso-glutamic acid-meso-diaminopimelic acid and the corresponding disaccharide-tetrapeptide N-acetylglucosamine-N-acetylmuramic acid-L-alanine-D-iso-glutamic acid-meso-diaminopimelic acid-D-alanine. The unique feature of these compounds is that the disaccharide has no reducing end group and that the muramic acid residue possesses an internal 1 leads to 6 anhydro linkage. The new lytic enzyme is designated as a murein: murein transglycosylase. Its possible role in the rearrangement of murein during cell growth and division is discussed.

Ammonium Sulfate↗
PubMed1996

Exposure to bacteria in swine-house dust and acute inflammatory reactions in humans.

Inhalation of swine-house dust may cause an acute airway inflammatory condition (organic dust toxic syndrome). Thirty-eight healthy subjects were exposed to swine dust while weighing swine for 3 h. We studied the correlation between acute health effects and the inhaled bacterial exposure markers peptidoglycan (the main constituent of the cell walls of gram-positive bacteria, but also present in lesser amounts in gram-negative bacteria) and lipopolysaccharides (LPS; present only in gram-negative bacteria). LPS activity in airborne dust was measured with the Limulus amebocyte lysate assay (LPS(LAL)), and the total LPS was estimated from 3-hydroxy fatty acids, which were measured with gas chromatography-mass spectrometry (GC-MS) (LPS(GC-MS)). Peptidoglycan was estimated from muramic acid measured with GC-MS. The median (25th to 75th percentile) concentration of inhalable dust was 21 (16 to 25) mg/m3. LPS(LAL) was 1.2 (0.9 to 1.4) microg/m3; LPS(GC-MS) was 3.9 (2.5 to 4.9) microg/m3; and the peptidoglycan concentration in airborne dust was 6.5 (2.7 to 13) microg/m3. All exposure markers correlated significantly with an increase in serum interleukin-6. LPS(LAL) showed the highest correlation (r2 = 0.29) and total inhaled dust the lowest (r2 = 0.09). LPS(LAL) also correlated with symptoms and with an increase in bronchial responsiveness and decrease in vital capacity (VC). Peptidoglycan, but not LPS(LAL), correlated with an increase in the blood granulocyte concentration and in body temperature. The results suggest that several microbial agents in inhaled swine-house dust may contribute to acute systemic health effects.

Administration, Inhalation↗
PubMed1987

Proteolysis in the gut of mosquito larvae results in further activation of the Bacillus sphaericus toxin.

Gut proteases from the larvae of the mosquito Culex pipiens convert the 43-kilodalton (kDa) toxin from Bacillus sphaericus 2362 to a 40-kDa peptide. The 50% lethal concentration of this peptide for tissue culture-grown cells of Culex quinquefasciatus was 1.0 microgram/ml (as determined by the intracellular ATP assay), 54-fold less than that of the 43-kDa peptide. Gut proteases from Anopheles gambiae and Aedes aegypti, as well as bovine pancreatic trypsin, also converted the 43-kDa protein to a 40-kDa peptide which was indistinguishable from the peptide formed by the proteases from C. pipiens with respect to its toxicity to tissue culture-grown cells of C. quinquefasciatus. Evidence for the in vivo conversion of the 43-kDa protein to the 40-kDa peptide was also obtained from experiments in which larvae of C. pipiens, Anopheles gambiae, and Aedes aegypti were fed crystals from B. sphaericus 2362. By using the exclusion of trypan blue as an indication of cell viability, it was shown that chitobiose, chitotriose, N-acetylmuramic acid, and N-acetylneuraminic acid decreased the toxicity of the 40-kDa peptide (from 100 to 50% mortality at about 10 mM concentrations of these sugars). Muramic acid, N-acetylgalactosamine, and N-acetylglucosamine were less effective, while several sugars had no effect, suggesting that the 40-kDa toxin binds to specific receptors on the cell membrane. The 40-kDa protein was less toxic to tissue culture-grown cells of Anopheles gambiae and Aedes dorsalis, and the same sugars which reduced the toxicity for cells of C. quinquefasciatus were also effective in reduction of toxicity for these cell lines.(ABSTRACT TRUNCATED AT 250 WORDS)

Aedes↗
PubMed1971

Chemical structure and immunological specificity of the streptococcal group e cell wall polysaccharide antigen.

The streptococcal group E cell wall polysaccharide antigen was extracted from strain K129 cells with hot trichloroacetic acid and purified. It contained rhamnose and glucose in a 2:1 molar ratio, 2% protein, 1% phosphorus, and was free of muramic acid and glycerol. No type polysaccharide antigen was present. The reaction of specific group E rabbit antiserum with the polysaccharide was effectively inhibited by d-glucose and beta-glucosides such as 1-methyl-beta-d-glucose, cellobiose, and gentiobiose. The 1-methyl-alpha-d-glucose was one-half as effective as the beta isomer. l-Rhamnose and N-acetyl-d-glucosamine were ineffective. Partial acid hydrolysis of the antigen followed by chromatographic separation of the oligosaccharides resulted in the isolation and analysis of five fractions. These fractions were di-, tri-, and tetrasaccharides. A study of these fractions by chemical analysis, reduction with borohydride, inhibition of the antigen-antibody reaction, release of glucose by beta-glucosidase, and other evidence indicate that beta-d-glucose is the immunodominant sugar in the antigen. A glucose-rhamnose trisaccharide (1:2 molar ratio) was the most effective inhibitor of the precipitin reaction; the glucose was readily released by beta-glucosidase, and one-half of the rhamnose was reduced with borohydride. This trisaccharide is considered to be a repeating unit in the native polysaccharide and probably has the following structure: O-beta-d-glucosyl-(1-2)-O-alpha-l-rhamnosyl- (1-4)-l-rhamnose. A glucose-rhamnose disaccharide in which the hexose and pentose are linked as in the trisaccharide was an effective inhibitor of the precipitin reaction. Strain K129 cells do not appear to contain a type polysaccharide antigen.

Journal Article↗
PubMed1983

Structure of linkage region between ribitol teichoic acid and peptidoglycan in cell walls of Staphylococcus aureus H.

The cell walls of Staphylococcus aureus H were found to contain mannosamine in an amount (28.1 nmol/mg) comparable to the content of muramic acid 6-phosphate. The acidic polymer fraction obtained by heating the cell walls at pH 2.5 was shown to contain mannosamine and glycerol in addition to the components of ribitol teichoic acid. Mild alkali treatment of this polymer fraction followed by gel filtration resulted in separation of a disaccharide N-acetylmannosaminyl(1 leads to 4)N-acetylglucosamine and the ribitol teichoic acid moiety that contained glycerol. Smith degradation of the reduction product from the same polymer fraction gave a fragment characterized as (1,2-ethylene-diol phosphate)-(glycerol phosphate)3-N-acetylmannosaminyl(1 leads to 4)N-acetylxylosaminitol. Thus, the ribitol teichoic acid chain in the cell walls is probably linked to peptidoglycan through a linkage unit, (glycerol phosphate)3-N-acetylmannosaminyl(1 leads to 4)N-acetylglucosamine.

Carbohydrate Conformation↗
PubMed1993

Characterization of the cell wall of Butyrivibrio species.

Most Butyrivibrio strains have been isolated from the gastrointestinal tract of animals and have been classified as Butyrivibrio fibrisolvens. A few strains isolated from human feces are designated as Butyrivibrio crossatus, the other species in this genus. Butyrivibrio fibrisolvens strains are anaerobic, curved rods that produce butyrate, but numerous studies have shown that these strains display considerable variations in phenotypic properties and heterogeneity in DNA relatedness. Although over 60 strains have been characterized in these respects, the cell wall structure of only a few strains has been studied. In this study, cell wall related properties of 12 strains representative of five DNA relatedness groups were examined. All strains were very sensitive to penicillin and other antibiotics that interfere with cell wall synthesis. Although an occasional resistant strain was found, most strains were sensitive to a variety of protein synthesis antibiotics that included aminoglycosides and tetracycline. In contrast, all strains were highly resistant to nalidixic acid. Peptidoglycans were isolated from seven B. fibrisolvens strains and Lachnospira multiparus. Compositional analyses indicated molar ratios of 0.7:2:2:1:0.8 for muramic acid, glucosamine, alanine, glutamic acid, and diaminopimelic acid, respectively, in all peptidoglycans, which also showed a low degree of cross-linking. A trichloroacetic acid extractable galactosamine-containing polysaccharide copurified with the Butyrivibrio peptidoglycans. Electron microscopy of thin sections showed all strains to possess a Gram-positive type of cell wall that was atypically thin (12-18 nm). Most strains also displayed external (surface) polysaccharide layers. Cytoplasmic inclusions and granules were evident in many strains and were composed of polysaccharides, on the basis of cell composition analyses. The findings that Butyrivibrio strains have overall similarities in cell wall properties, but differences in DNA relatedness, suggest that these organisms should be classified as several more species in the same genus or family.

Anti-Bacterial Agents↗
PubMedDate not supplied

Major protein components in the cell envelope of Clostridium tyrobutyricum.

The overall composition of the Clostridium tyrobutyricum cell envelope did not vary significantly during cell growth and was characterized by a high protein content (about 40% dry weight). Teichoic and teichuronic acids were absent and the neutral sugar content low. Insoluble peptidoglycan represented only 10-12% of the cell envelope (dry weight basis); it contained glucosamine, muramic acid, alanine, diaminopimelic acid and glutamic acid (molecular ratio 1/1/2/1/1). SDS-PAGE revealed the presence of about 50 proteins in this cell envelope; however, one high molecular weight protein was largely predominant. They were not covalently bound to the peptidoglycan and their relative amounts were practically constant through cell growth and with various extraction treatments. A brief heat treatment of whole cells in PBS caused selective release of the major cell envelope proteins together with flagellin; this method was used to characterize these proteins in 37 strains of C. tyrobutyricum and some other clostridia. The major envelope proteins had molecular weights ranging from 96 to 145 Kd and the flagellins from 32 to 72 Kd.

Bacterial Proteins↗
PubMed1991

Dependence of lysozyme-catalysed solubilization of Proteus mirabilis peptidoglycan on the extent of O-acetylation.

The degree of peptidoglycan O-acetylation in 14 strains of Proteus mirabilis has been accurately determined by a procedure which employs the quantitation of mild-base-released acetic acid by HPLC, and the estimation of peptidoglycan concentration by cation-exchange amino acid analysis. The beta-D-N,6-O-diacetylmuramyl content of all isolated and purified peptidoglycans was ranged 20-52.8%, relative to the total muramic acid concentration. Each of the O-acetylated peptidoglycans was found to be resistant to solubilization by both human and hen egg-white lysozymes and for hen egg-white lysozyme, the extent of this resistance was dependent upon the degree of O-acetylation. The steady-state parameters, Km and V, for the hen-egg-white-lysozyme-catalysed solubilization of various peptidoglycan preparations were determined at pH 6.61 and 25 degrees C. Values of Km for the different peptidoglycan samples were found to increase with increasing O-acetylation, whereas with V no such relationship appeared to exist. An increase in the overall change in the standard Gibbs free energy of activation [delta(delta G#)], a consequence of increasing O-acetylation, was observed, and is shown to result from the weaker affinity of the enzyme for the modified substrates.

Acetylation↗
PubMed1993

Compositional analysis of peptidoglycan by high-performance anion-exchange chromatography.

A high-performance anion-exchange chromatography method with pulsed-amperometric detection has been developed for the simultaneous analysis of both amino acids and amino sugars and applied to the compositional analysis of peptidoglycan hydrolysates. Chromatography of the acid hydrolysis products was performed on a CarboPac PA-1 anion-exchange column, with pulsed-amperometric detection. Complete resolution of the two amino sugars (glucosamine and muramic acid) and eight of the nine amino acids (Ala, diaminobutyric acid, diaminopimelic acid, Glu, Gly, homoserine, Lys, Orn, and Ser) known to occur in various peptidoglycans was achieved within 70 min. Only homoserine and glycine (retention times 26.8 and 26.9 min, respectively) were not resolved by this procedure, but the simultaneous occurrence of these two amino acids in peptidoglycan is extremely rare. Reproducibility of the separations was shown to be very high and detection limits exceeded 10 pmol for glucosamine. This convenient and simple analysis was applied to the quantitation of many crude peptidoglycan samples isolated from the species of the Proteeae (Proteus, Providencia, and Morganella) for the determination of the extent of peptidoglycan O-acetylation.

Acetylation↗