Relationship between lysostaphin endopeptidase production and cell wall composition in Staphylococcus staphylolyticus

Abstract

Mutants of Staphylococcus staphylolyticus incapable of producing an extracellular staphylolytic glycylglycine endopeptidase were isolated and found to have cells in the population susceptible to lysis by this enzyme, as did the wild-type organism under conditions in which the endopeptidase was not produced. These results suggest that cultures of this organism normally contain a heterogeneous population of cells with regard to cell wall composition and susceptibility to the enzyme. Production of the endopeptidase appears to act as a selective pressure which removes the susceptible cells in the population as the enzyme appears in the medium. A comparison of the peptidoglycan of the wild-type organism grown under conditions in which the endopeptidase was produced with that of this organism grown under nonproducing conditions and with those of endopeptidaseless mutants showed that in the presence of the endopeptidase the cell population had peptidoglycan with shorter peptide cross bridges and a greater percentage of serine in these cross bridges than was found in cells grown in the absence of the enzyme. The inability of the endopeptidase to hydrolyze glycylserine and serylglycine peptide bonds suggests that at least part of the resistance this organism has to the endopeptidase is due to relative amounts of serine found in the peptide cross bridges of some cells in the population.

The length of lipoteichoic acid polymers controlsStaphylococcus aureuscell size and envelope integrity

“…Lysostaphin is an endopeptidase produced in other Staphylococci spp. that hydrolyzes the peptide cross bridges between PG strands (47, 48). We found that Δ ltaA and Δ ugtP mutants were substantially more susceptible to these enzymes than were wild type cells (Fig.…”

Simple screening method for identification of nonpleiotropic mutants for exoenzyme production

“…ml of a clear agar underlay (1.5 g of Bacto agar per 100 ml of deionized water). Figure 1 shows that spontaneous or N-methyl-N'-nitro-Nnitrosoguanidine-induced variants of S. staphylolyticus (10) with different eyoenzyme-producing capabilities can be identified easily with the screening medium. The wild-type organism produced all three exoenzymes and, therefore, had a clear zone of cell lysis and casein hydrolysis surrounding each colony (Fig.…”

“…A variant that had a slightly turbid zone around each colony (Fig. 1B) was found on subsequent assay of culture supernatant (10,11) to have lost the ability to produce active endopeptidase, although it still produced active protease and hexosaminidase. These additional assays were required to identify the specific enzyme defect, because the medium did not allow a differentiation among the three types of single mutants.…”

PROTECTIVE EFFECT OF LYSOSTAPHIN FROM STAPHYLOCOCCUS SIMULANS AGAINST GROWTH OF STAPHYLOCOCCUS AUREUS IN MILK AND SOME OTHER FOOD PRODUCTS

“…Mother S. simulans is also resistant against lysostaphin due to the production of immunity factor, incorporating the serine residues into the interpeptide bridges. It causes lysostaphin to be unable to hydrolyse Gly‐Ser or Ser‐Gly peptide bonds (Robinson et al. 1979; Heath et al.…”