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An exocytoplasmic endonuclease with restriction function in Streptomyces antibioticus.
C G de los Reyes-Gavilan1, J F Aparicio, C Barbes
1Department of Microbiology, Faculty of Medicine, University of Oviedo, Spain.
Journal of Bacteriology
|March 1, 1988
Summary
Streptomyces antibioticus produces an endo-DNase enzyme that degrades DNA. This enzyme influences actinophage growth and plaque size, suggesting a role in in vivo restriction.
Area of Science:
- Microbiology
- Molecular Biology
- Enzymology
Background:
- Streptomyces antibioticus harbors a potent endo-DNase enzyme.
- This nuclease is localized between the cytoplasmic membrane and cell wall.
- The enzyme exhibits broad substrate specificity, degrading various DNA types.
Purpose of the Study:
- To investigate the role of Streptomyces antibioticus endo-DNase in actinophage interactions.
- To determine the influence of growth media on nuclease synthesis and phage behavior.
- To elucidate the enzyme's potential function in in vivo restriction.
Main Methods:
- Enzyme characterization and DNA degradation assays.
- Actinophage plaque assays on different growth media.
- Analysis of phage growth on a nuclease-deficient S. antibioticus mutant.
Main Results:
- The endo-DNase completely degraded all tested DNA substrates in vitro.
- Nuclease synthesis varied with growth medium, impacting phage plaque size.
- Phage efficiency of plating and growth were modulated by the host nuclease presence.
Conclusions:
- The S. antibioticus endo-DNase significantly affects actinophage plaque size and growth efficiency.
- Host nuclease activity, combined with phage adsorption, dictates phage-host interactions.
- The endo-DNase can function as an in vivo restriction system under specific conditions.