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Sucrose transport by Streptococcus mutans. Evidence for multiple transport systems
Biochimica Et Biophysica Acta
|November 22, 1982
Summary
Streptococcus mutans utilizes at least three distinct sucrose transport systems. Two are phosphoenolpyruvate-dependent phosphotransferases, while a third, high-affinity system functions during abundant sucrose conditions.
Area of Science:
- Microbiology
- Molecular Biology
- Biochemistry
Background:
- Streptococcus mutans relies on sucrose for growth and acid production, contributing to dental caries.
- Understanding sucrose transport mechanisms is crucial for developing strategies to inhibit S. mutans activity.
Purpose of the Study:
- To elucidate the mechanisms of sucrose transport in Streptococcus mutans.
- To characterize the different sucrose transport systems present in S. mutans, including their kinetics and regulation.
Main Methods:
- Utilized washed cells of selected mutant and wild-type Streptococcus mutans strains.
- Incubated cells with radiolabeled sucrose in the presence of fluoride.
- Analyzed sucrose uptake kinetics and characterized transport systems using Km values and mutant analysis.
Main Results:
- Identified at least three distinct sucrose transport systems in S. mutans.
- Two systems are phosphoenolpyruvate-dependent phosphotransferases (PTS) with low apparent Km values.
- A third, non-PTS system (TTS) exhibits a high apparent Km and functions under sucrose abundance.
Conclusions:
- S. mutans possesses multiple, distinct sucrose transport systems adapted to fluctuating environmental sucrose levels.
- The high-affinity PTS systems are regulated by glucose, while the high-Km TTS system operates under nutrient-rich conditions.
- These findings provide insights into S. mutans' metabolic adaptability and cariogenic potential.
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