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A Bacillus subtilis dipeptide transport system expressed early during sporulation
C Mathiopoulos1, J P Mueller, F J Slack
1Department of Molecular Biology and Microbiology, Tufts University Health Sciences Campus, Boston, Massachusetts 02111.
Molecular Microbiology
|August 1, 1991
Summary
The Bacillus subtilis dciA operon encodes a dipeptide transport system. This system is crucial for proline auxotrophs to utilize dipeptides like Pro-Gly as a sole proline source during sporulation.
Area of Science:
- Molecular Biology
- Microbiology
- Bacterial Physiology
Background:
- Two Bacillus subtilis DNA segments, dciA and dciB, show rapid transcript accumulation during sporulation.
- These segments are part of a larger 6.2 kb transcription unit, identified as the dciA operon.
Purpose of the Study:
- To elucidate the function of the dciA operon.
- To determine if the dciA operon is involved in nutrient transport, specifically peptide transport.
Main Methods:
- Sequence analysis of the dciA operon to predict protein functions.
- Construction and analysis of a null mutation in the dciAE gene.
- Growth assays of a proline auxotroph using dipeptides as the sole proline source.
Main Results:
- Sequence analysis revealed putative peptide transport system components, with DciAE homologous to known peptide-binding proteins.
- A null mutation in dciAE impaired growth of a proline auxotroph when Pro-Gly was the only proline source.
- These findings strongly suggest the dciA operon encodes a functional dipeptide transport system.
Conclusions:
- The dciA operon in Bacillus subtilis encodes a dipeptide transport system.
- This system plays a significant role in nutrient acquisition, particularly for proline auxotrophs utilizing dipeptides.
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