Rhodobacter sphaeroides chemoreceptor, McpH. Expression and functional analysis in E.coli.

KARINA HERRERA SEITZ; CLAUDIA STUDDERT

Puerto Madryn

Congreso; 46º Congreso de SAIB (Sociedad Argentina de invedtigaciones Bioquímicas); 2010

SAIB

Chemoreceptors (MCPs) are transmembrane proteins responsible for sensing environmental stimuli and transducing them to bacterial flagellar motors. MCPs are classified into seven classes, according to the length of their highly conserved coiled coil cytoplasmic domain. E. coli chemoreceptors, belonging to the 36H class, are organized in trimers of dimers composed by dimers of different specificities. In order to assess whether functional interactions within the signaling complex and higher order MCP organization represent conserved features, we expressed heterologous receptors in E. coli cells. Here we report cloning and expression of McpH, a putative organic acid receptor from Rhodobacter sphaeroides that belongs to the 34H class. McpH was able to generate clockwise flagellar rotation when expressed as the only receptor in E. coli cells, indicating its ability to form active signaling complexes with the histidine kinase CheA and the coupling protein CheW. Moreover, McpH was able to form mixed trimers of dimers with E. coli MCPs as indicated by in vivo crosslinking assays. Taken together, these results suggest that MCPs from different classes share their higher order organization and functional interactions with other chemotaxis proteins.