ATP-binding RNA helicase involved in mitochondrial RNA metabolism. Required for maintenance of mitochondrial DNA. ATP + H2O = ADP + H(+) + phosphate The Q motif is unique to and characteristic of the DEAD box family of RNA helicases and controls ATP binding and hydrolysis. Present with 736 molecules/cell in log phase SD medium. Belongs to the DEAD box helicase family. MRH4 subfamily.