Interaction of Epulopiscium Methyl‐Accepting Chemotaxis Proteins with E. Coli CheW and CheA

Abstract

Listen

Translate article

Epulopiscium sp. Type B is a large (up to 250 μm length) unculturable gram positive bacterium that grows symbiotically in the gut of the surgeonfish Naso tonganus. To further understand the unique biology of this organism, we recombinantly expressed GST fusions of Epulo methyl accepting chemotaxis sensory transducers (MCP) in E.coli. MCPs are responsible for sensing and binding extracellular ligands as well as recognizing pH and temperature changes. In E. Coli the MCP interacts indirectly with CheA (sensory kinase) through CheW (coupling protein). The degree of sensory kinase activity controls the motor complex resulting in taxis towards or away from the stimulus. Aligned with the Tar MCP in E. Coli, Epulo MCP 3 displays a 16.2% identity and 28.8% similarity. Epulopiscium MCP 6 has an 18.6% identity and 33.7% similarity. Epulo CheW was aligned with E. Coli CheW and shows 44.9% conservation and 26.9% identity. Epulo CheA has 30.8% identity and 48% similarity when compared with CheA from E. Coli. As a result Epulo MCPs should theoretically interact with CheA through CheW in an in vitro pull‐down assay. These protein interaction studies lay the foundation for future study of Epulo chemotaxis in E. Coli using motility “swarm” assays. This may help to elucidate the environment in which Epulo lives, and its role in symbiosis with the surgeonfish. This project was funded by the Hartwick College Department of Chemistry.