Characterization of Bacterial Chemosensory Protein, FrzE, in Myxococcus xanthus

Abstract

The life cycle processes like fruiting body formation and vegetative swarming in Myxococcus xanthus, a gram-negative rod-shaped bacterium, require the involvement of controlled movements by gliding motility on surfaces, in response to environmental cues. A chemotaxis pathway, the Frz signal transduction system plays a major role in these cellular reversals. The domains of the proteins encoded by frz genes are homologous to proteins involved in chemotaxis signaling, which facilitates two-component signal transduction. FrzE, a two-component histidine kinase, is a part of the Frz signal transduction system, which autophosphorylates on a conserved histidine residue upon receiving the signal and helps in the further transduction of the signal to downstream components. We characterized the phosphoacceptor domain and the catalytic domain of FrzE, and measured the ATPase activity of FrzE. HPT domain has been purified, crystallized, and diffraction data obtained. ATPase assay shows that FrzE has catalytic activity. Preliminary experiments for cloning the HATPase domain were carried out. Structural analysis of HATPase domains belonging to the HATPase superfamily helped in identifying the conserved residues essential for catalysis. The project is being continued to refine the crystal structure of the HPT domain, purification and interaction studies of the catalytic domain, and further quantification of the ATPase activity of FrzE.