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Physical properties and the fine structure of proteocines
Zentralblatt Fur Bakteriologie, Parasitenkunde, Infektionskrankheiten Und Hygiene. Erste Abteilung Originale. Reihe A: Medizinische Mikrobiologie Und Parasitologie
|August 1, 1976
Summary
Proteus mirabilis and Proteus vulgaris proteocines are particulate bacteriocins. These phage-tail-like structures kill sensitive bacteria by shrinking cell contents after adsorption.
Area of Science:
- Microbiology
- Bacteriology
- Molecular Biology
Background:
- Proteocines are bacteriocins produced by Proteus species.
- Bacteriocins are ribosomally synthesized antimicrobial peptides.
Purpose of the Study:
- To characterize proteocines from Proteus mirabilis and Proteus vulgaris.
- To elucidate the structure and mechanism of action of these proteocines.
Main Methods:
- Proteocine purification using ammonium sulfate precipitation and ultracentrifugation.
- Characterization by trypsin sensitivity, thermal stability, and UV absorption.
- Structural analysis via electron microscopy.
- Mechanism of action investigation through adsorption studies.
Main Results:
- Proteocine preparations were particulate, trypsin-resistant, and sensitive to heat and freeze-thaw.
- Purification revealed activity associated with material absorbing at 257 mu.
- Electron microscopy showed phage-tail-like structures with sheath, core, and base-plate with fibers.
- Adsorption to sensitive cells led to cytoplasmic membrane shrinkage and cell death, without cell wall disruption.
Conclusions:
- Proteocines from P. mirabilis and P. vulgaris share structural and functional similarities.
- The observed phage-tail-like structure suggests a unique delivery mechanism for these bacteriocins.
- The mechanism of cell death involves cytoplasmic membrane damage and content shrinkage.