Probable DEAD-box RNA helicase. May work in conjunction with the cold shock proteins to ensure proper initiation of transcription at low and optimal temperatures. Unwinds dsRNA in both 5'- and 3'-directions and shows RNA-dependent ATPase activity (By similarity). Probably has a somewhat redundant function with CshA, as cshA can partially complement the growth effects of a cshB deletion. ATP + H2O = ADP + H(+) + phosphate Induced at 10 degrees Celsius. Longer lag phase at 20 degrees Celsius, wild-type growth rate at 30 degrees Celsius, impaired growth at 10 degrees Celsius. At 12 degrees Celsius cells form very long filaments, with incompletely divided, thickened internal membranes. Effects on growth at reduced temperature are partially complemented by cshA, suggesting the 2 genes have a partially redundant function. Decreased growth in the presence of H(2)O(2) and diamide. Belongs to the DEAD box helicase family. CshB subfamily.