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Phosphorylated tyrosine in the flagellum filament protein of Pseudomonas aeruginosa
K Kelly-Wintenberg1, T Anderson, T C Montie
1Department of Microbiology, University of Tennessee, Knoxville 37996.
Abstract:
Purified flagella from two strains of 32P-labeled Pseudomonas aeruginosa were shown to be phosphorylated. This was confirmed by autoradiography of flagellin protein in polyacrylamide gels. Thin-layer electrophoresis and autoradiography of flagellin partial hydrolysates indicated that phosphotyrosine was the major phosphorylated amino acid. High-pressure liquid chromatographic analysis confirmed the presence of phosphotyrosine in flagellum filament protein. Preliminary data indicated that less than one tyrosine per subunit was phosphorylated. No evidence was found for phosphorylation of serine or threonine. A function related to tyrosine phosphorylation has not been determined.
Insights
Pseudomonas aeruginosa flagella are phosphorylated, with phosphotyrosine identified as the primary modified amino acid. This phosphorylation occurs at a low level on flagellin subunits, and its specific function remains undetermined.
Area of Science:
- Microbiology
- Molecular Biology
- Biochemistry
Background:
- Pseudomonas aeruginosa flagella are crucial for motility and host interaction.
- Protein phosphorylation is a key regulatory mechanism in bacterial signaling pathways.
Purpose of the Study:
- To investigate the phosphorylation status of purified Pseudomonas aeruginosa flagella.
- To identify the specific amino acids involved in flagellar phosphorylation.
Main Methods:
- Purification of flagella from 32P-labeled Pseudomonas aeruginosa strains.
- Analysis using polyacrylamide gel electrophoresis, autoradiography, thin-layer electrophoresis, and high-pressure liquid chromatography.
Main Results:
- Purified flagella proteins were confirmed to be phosphorylated.
- Phosphotyrosine was identified as the major phosphorylated amino acid in flagellin.
- Phosphorylation occurred at less than one tyrosine per subunit, with no evidence of serine or threonine phosphorylation.
Conclusions:
- Flagellin from Pseudomonas aeruginosa flagella undergoes tyrosine phosphorylation.
- The functional significance of this specific tyrosine phosphorylation in flagella remains to be elucidated.