Evidence that the PBP 5 synthesis repressor (psr) of Enterococcus hirae is also involved in the regulation of cell wall composition and other cell wall-related properties
| Autor: | Lolita Daneo-Moore, R. Kariyama, Gerald D. Shockman, Orietta Massidda |
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| Rok vydání: | 1996 |
| Předmět: |
Rhamnose
Penicillin Resistance Repressor Buffers medicine.disease_cause Microbiology Phosphates Cell wall chemistry.chemical_compound Bacteriolysis Bacterial Proteins Cell Wall Enterococcus hirae medicine Molecular Biology Gene Mutation biology Protoplasts Structural gene Penicillin G biology.organism_classification Repressor Proteins Osmotic Fragility chemistry Biochemistry Muramidase Peptidoglycan Enterococcus Research Article |
| Zdroj: | Scopus-Elsevier |
| ISSN: | 1098-5530 0021-9193 |
| DOI: | 10.1128/jb.178.17.5272-5278.1996 |
| Popis: | psr has been reported by M. Ligozzi, F. Pittaluga, and R. Fontana, (J. Bacteriol. 175:2046-2051, 1993) to be a genetic element located just upstream of the structural gene for the low-affinity penicillin-binding protein 5 (PBP 5) in the chromosome of Enterococcus hirae ATCC 9790 and to be involved in the repression of PBP 5 synthesis. By comparing properties of strains of E. hirae that contain a full-length, functional psr with those of strains that possess a truncated form of the gene, we have obtained data that indicate that psr is involved in the regulation of several additional surface-related properties. We observed that cells of strains that possessed a truncated psr were more sensitive to lysozyme-catalyzed protoplast formation, autolyzed more rapidly in 10 mM sodium phosphate (pH 6.8), and, in contrast to strains that possess a functional psr, retained these characteristics after the cultures entered the stationary growth phase. Cellular lytic properties did not correlate with differences in the cellular contents of muramidase-1 or muramidase-2, with the levels of PBP 5 produced, or with the penicillin susceptibilities of the strains. However, a strong correlation was observed with the amounts of rhamnose present in the cell walls of the various strains. All of the strains examined that possessed a truncated form of psr also possessed approximately one-half of the rhamnose content present in the walls of strains that possessed a functional psr. These data suggest that psr is also involved in the regulation of the synthesis of, or covalent linkage to the cell wall peptidoglycan of, a rhamnose-rich polysaccharide. These differences in cell wall composition could be responsible for the observed phenotypic differences. However, the multiple effects of psr suggest that it is part of a global regulatory system that, perhaps independently, affects several cell surface-related properties. |
| Databáze: | OpenAIRE |
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