Identification of proteins exhibiting in vitro RNA chaperone activity through gradient profiling in the Lyme disease spirochete, Borrelia burgdorferi.

RNA-binding proteins (RBPs) play key roles in regulating gene expression across all domains of life. However, relatively few RBPs have been discovered and characterized in Borrelia (Borreliella) burgdorferi, the causative agent of Lyme disease. We utilized gradient profiling to identify putative RBPs that co-sediment with small RNAs (sRNAs) and nascent mRNAs. The previously hypothetical proteins BB0749, BB0713 and BB0796, as well as the chemotaxis-related protein CheY2 and the flagella-associated protein FlgV demonstrated RNA unwinding (structural remodeling), RNA annealing, and strand displacement activity. Moreover, in vivo co-IP assays demonstrated BB0749 binds RNA in B. burgdorferi.