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Phosphorylation and processing of the quorum-sensing molecule autoinducer-2 in enteric bacteria
Karina B Xavier1, Stephen T Miller, Wenyun Lu
1Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544-1014, USA.
ACS Chemical Biology
|February 6, 2007
Summary
Bacteria use quorum sensing for communication. This study reveals how enteric bacteria internalize and modify autoinducer-2 (AI-2) to disrupt competitor communication, a novel inter-species signaling interference mechanism.
Area of Science:
- Microbiology
- Bacterial Communication
- Biochemistry
Background:
- Quorum sensing allows bacteria to communicate population density using autoinducers.
- Autoinducer-2 (AI-2) is synthesized by LuxS and plays a role in inter-species communication.
- Enteric bacteria internalize AI-2 via the LuxS regulated (Lsr) transporter, potentially to interfere with other species.
Purpose of the Study:
- To elucidate the molecular mechanism by which enteric bacteria process internalized AI-2.
- To identify the specific molecule that induces the lsr operon.
- To understand how AI-2 sequestration by enteric bacteria impacts inter-species communication.
Main Methods:
- Investigated the phosphorylation of 4,5-dihydroxy-2,3-pentanedione (DPD) by the kinase LsrK.
- Assessed the binding of phosphorylated DPD (P-DPD) to the repressor LsrR.
- Studied the enzymatic cleavage of P-DPD by LsrG.
Main Results:
- The kinase LsrK phosphorylates the open form of DPD to P-DPD.
- P-DPD specifically binds to the repressor LsrR, indicating it is the lsr operon inducer.
- LsrG cleaves P-DPD into 2-phosphoglycolic acid.
Conclusions:
- Enteric bacteria sequester and degrade AI-2 through a phosphorylation and cleavage pathway.
- This mechanism allows enteric bacteria to disable the quorum sensing communication of competing bacteria.
- The findings reveal a novel strategy for bacterial interference in mixed microbial communities.
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