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Method for Efficient Refolding and Purification of Chemoreceptor Ligand Binding Domain
Published on: December 12, 2017
The Bacillus subtilis chemoreceptor McpC senses multiple ligands using two discrete mechanisms
George D Glekas1, Brendan J Mulhern, Abigail Kroc
1Department of Biochemistry, University of Illinois, Urbana, Illinois 61801, USA.
The Journal of Biological Chemistry
|October 6, 2012
Summary
Bacillus subtilis chemoreceptor McpC directly senses 11 amino acids and indirectly senses 4 others via binding lipoproteins. This reveals the complex mechanism of amino acid chemotaxis in this bacterium.
Area of Science:
- Microbiology
- Molecular Biology
- Biochemistry
Background:
- Bacillus subtilis exhibits chemotaxis towards all 20 L-amino acids.
- The chemoreceptor McpC is crucial for sensing 19 of these amino acids.
Purpose of the Study:
- To elucidate the amino acid-sensing mechanism of the Bacillus subtilis chemoreceptor McpC.
- To identify the specific amino acids sensed directly and indirectly by McpC.
Main Methods:
- In vitro binding assays to determine direct amino acid interaction with McpC's sensing domain.
- Sequence analysis to identify structural features of the McpC sensing domain (dual PAS domains).
- Mutagenesis studies and identification of binding lipoproteins associated with amino acid transporters.
Main Results:
- McpC alone mediates chemotaxis to 17 amino acids.
- Eleven amino acids directly bind the McpC sensing domain.
- Four amino acids (arginine, glutamine, lysine, methionine) are sensed indirectly.
- Specific lipoproteins (ArtP, GlnH, MetQ, YckB) were identified as binding partners for indirect sensing, with ArtP, MetQ, and YckB also binding McpC.
Conclusions:
- McpC utilizes both direct and indirect sensing mechanisms to detect a wide range of amino acids.
- Lipoproteins like ArtP, GlnH, MetQ, and YckB play a key role in the indirect chemotaxis pathway.
- This study deepens the understanding of the sophisticated amino acid chemotaxis system in Bacillus subtilis.
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