Characterization of cyclic di-GMP binding by the sole Borrelia burgdorferi and Borrelia hermsii PilZ domain-containing proteins

• Main Author: Mallory, Katherine Louise
• Format: Others
• Published: VCU Scholars Compass 2013
• Subjects: Medicine and Health Sciences
• Online Access: http://scholarscompass.vcu.edu/etd/532; http://scholarscompass.vcu.edu/cgi/viewcontent.cgi?article=1531&context=etd

Borrelia burgdorferi and Borrelia hermsii cause Lyme disease and relapsing fever, respectively. These spirochetes are maintained in an enzootic cycle, involving tick vectors and mammalian hosts. Differential gene expression is central in their survival in various environmental conditions. C-di-GMP has been demonstrated to be important in bacterial adaptation. Borrelia deletion mutant phenotypes have shown that c-di-GMP regulates motility, infectivity, and enzootic cycle progression. As the only known receptors encoded by Borrelia, PlzA and PlzC characterization is necessary in delineating c-di-GMP roles within the cell. In this study, biochemical, biophysical, and FRET methods demonstrated that these proteins exhibit a structural rearrangement when binding c-di-GMP likely significant to downstream activities. Substitution of a highly conserved residue within PlzA altered the structure and charge of the PilZ domain, leading to abolished binding. PlzA and PlzC functionality studies are vital to discover mechanisms of c-di-GMP-mediated regulation of motility and host invasion by the Borrelia.