A genomic glance at the chemosensory systems of a polyaromatic-hydrocarbon chemotactic strain

GASPEROTTI A. F.; STUDDERT C. A. ; HERRERA SEITZ M. K.

Mar del Plata

Congreso; 51st Annual Meeting Argentine Society for Biochemistry and Molecular Biology; 2015

SAIB

Halomonas sp. KHS3 is a hydrocarbon-degrading microorganism isolated from seawater of Mar del Plata harbor. This strain is able to grow on aromatic hydrocarbons and shows chemotactic responses to these compounds. The whole genomic sequence of this strain was recently obtained (Gasperotti et al., 2015). In order to identify the proteins involved in the detection of hydrocarbons, the chemosensory systems present in the genome of Halomonas sp. KHS3 were analyzed. Based on the preliminary annotation of the genome in the RAST server, we found 24 chemoreceptors (MCPs), and two different copies each of genes coding for chemotaxis proteins. These genes were found to be organized in two clusters: one showing a gene organization similar to that described for the well-known E. coli chemotaxis cluster and the other showing a different organization. This second cluster includes an MCP of different class than the other MCP genes and a diguanylate cyclase with a receiver domain, suggesting involvement of this system in c-di-GMP levels control. A comparative study between 49 Halomonas available genomes showed that half of them have similar organization of chemosensory clusters. The predicted ligand-binding domains of the 24 MCPs were subjected to structural modeling and their genomic context was analyzed, in order to get information about their likely participation in hydrocarbon detection.