Has RNA-stimulated ATPase activity and RNA helicase activity (PubMed:24367266). Involved in global regulation of gene expression (PubMed:21814569). Could be involved in RNA processing and post-transcriptional gene regulation (PubMed:24367266). Essential for both tick transmission and mouse infection (PubMed:24367266). ATP + H2O = ADP + H(+) + phosphate Disruption of the gene results in the modulation of the expression of about 180 proteins and in a complete loss in the ability of the spirochetes to infect mice by needle inoculation. Belongs to the DEAD box helicase family. DEAH subfamily.