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Evidence for a phosphoenolpyruvate dependent sugar-phosphotransferase system in the mollicute Acholeplasma florum
J Navas-Castillo1, F Laigret, A Hocquellet
1Laboratoire de biologie cellulaire et moléculaire, Institut National de la Recherche Agronomique et Université de Bordeaux II, Villenave d'Ornon, France.
Abstract:
In order to confirm the presence of a phosphoenolpyruvate (PEP)-dependent sugar-phosphotransferase system (PTS) in the mollicute Acholeplasma florum we studied the ability of cell free extracts of this organism to phosphorylate glucose and/or fructose in the presence of PEP. We also cloned and sequenced a DNA fragment coding for a putative polypeptide showing significant similarity with the enzyme II of the beta-glucoside PTS of Escherichia coli. Taken together, these results show that A florum possesses a fructose-PTS, but not a glucose-PTS, and that the amino acid sequence deduced from the DNA fragment is related to beta-glucoside and sucrose enzymes II of PTS from various bacteria.
Insights
Acholeplasma florum utilizes a fructose-specific phosphoenolpyruvate (PEP)-dependent sugar-phosphotransferase system (PTS). Genetic analysis revealed a gene encoding a protein similar to bacterial enzyme II components of PTS, confirming fructose transport.
Area of Science:
- Microbiology
- Molecular Biology
- Biochemistry
Background:
- Mollicutes are bacteria lacking cell walls.
- Phosphoenolpyruvate (PEP)-dependent sugar-phosphotransferase systems (PTS) are crucial for sugar uptake and metabolism in many bacteria.
- The presence and specificity of PTS in Acholeplasma florum were previously uncharacterized.
Purpose of the Study:
- To investigate the presence and substrate specificity of a PEP-dependent sugar-phosphotransferase system (PTS) in Acholeplasma florum.
- To identify and characterize genes involved in sugar transport in A. florum.
Main Methods:
- Cell-free extracts of A. florum were used to assay phosphorylation of glucose and fructose in the presence of PEP.
- A DNA fragment encoding a putative PTS enzyme II component was cloned and sequenced.
- Bioinformatic analysis was performed to compare the deduced amino acid sequence with known PTS enzymes.
Main Results:
- A. florum cell-free extracts demonstrated the ability to phosphorylate fructose, but not glucose, in the presence of PEP, indicating a fructose-PTS.
- A DNA fragment was successfully cloned and sequenced, revealing a gene with significant homology to enzyme II of the beta-glucoside PTS from Escherichia coli.
- The deduced amino acid sequence showed relatedness to beta-glucoside and sucrose enzyme II components of PTS from various bacterial species.
Conclusions:
- Acholeplasma florum possesses a specific fructose-PTS, facilitating fructose uptake and phosphorylation.
- The identified gene likely encodes a fructose-specific enzyme II component of the PTS in A. florum.
- These findings contribute to understanding sugar metabolism and transport mechanisms in mollicutes.