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Bacteriophage MX-1: properties of the phage and its structural proteins
Abstract:
Bacteriophage MX-1 is a virulent DNA phage for Myxococcus. The host range includes strains of Myxococcus xanthus, M. fulvus and M. virescens. The phage has a sedimentation coefficient (S degrees 20,w) of 1145S and a density of 1-531 g/ml. By using SDS-polyacrylamide gel electrophoresis, 23 phage proteins with apparent mol. wt. between 10000 and 150000 were resolved. Gel filtration in the presence of non-ionic detergent partially resolved the proteins. The fraction excluded from Sephadex G-100, fraction 1, contains two glycoproteins. Fraction 1 was resolved into three fractions (1-1, 1-2 and 1-3) by chromatography on Sephadex G-200. The glycoproteins were present in fraction 1-2; all the proteins from this fraction were derived from the phage tail. Comparison of the amino-acid, hexosamine and neutral-sugar compositions of the two glycoproteins showed that they are distinct molecular species; the smaller molecule is not a subunit of the larger. The significance of these findings is discussed and compared with the proteins of the tails of T-even phage of Escherichia coli.
Insights
Bacteriophage MX-1, a virulent DNA phage, infects Myxococcus species. Its tail proteins include two distinct glycoproteins, not subunits, offering insights into phage structure.
Area of Science:
- Microbiology
- Molecular Biology
- Virology
Background:
- Bacteriophage MX-1 is a virulent DNA phage that infects Myxococcus bacteria.
- Understanding phage structure is crucial for phage therapy and molecular biology.
Purpose of the Study:
- To characterize the proteins of Bacteriophage MX-1, focusing on its tail glycoproteins.
- To compare these proteins with those of other known bacteriophages.
Main Methods:
- Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) to resolve phage proteins.
- Gel filtration chromatography (Sephadex G-100 and G-200) to isolate and purify proteins.
- Biochemical analysis of amino acid, hexosamine, and neutral sugar composition.
Main Results:
- SDS-PAGE resolved 23 proteins in Bacteriophage MX-1.
- Two distinct glycoproteins were identified in the phage tail fraction.
- Compositional analysis confirmed these glycoproteins are separate molecular entities, not subunits.
Conclusions:
- Bacteriophage MX-1 possesses unique tail glycoproteins.
- These findings contribute to the understanding of bacteriophage structure and evolution.
- Comparison with T-even phage proteins provides evolutionary context.