DEAD-box RNA helicase probably involved in RNA degradation. Unwinds dsRNA in both 5'- and 3'-directions (By similarity). Background RNA-dependent ATPase activity is stimulated about 5-fold by RNaseJ (rnj). Stimulates the dsRNase activity of RNase J. ATP + H2O = ADP + H(+) + phosphate Homodimer (By similarity). Interacts with RNase J (rnj), might be a member of a minimal RNA degradosome complex. The RNaseJ-RhpA complex co-localizes with 70S ribosomes and polysomes; remains associated with ribosomes in the absence of RNase J. Not essential, it can be deleted. RNase J remains associated with the ribosomes and polysomes. Belongs to the DEAD box helicase family.