DEAD-box RNA helicase involved in cold tolerance, motility, and tolerance to heat, alkali and oxidative stress. ATP + H2O = ADP + H(+) + phosphate By growth at 3 degrees Celsius (PubMed:22564273), and 3.5% ethanol (PubMed:22820328). Growth rate decreased at 37 and 25 degrees Celsius, almost completely stopped at 3 degrees Celsius. No motility at 25 or 3 degrees Celsius (PubMed:22564273). Decreased growth at 42 degrees Celsius, pH 9.4 and in the presence of 5 mM H(2)O(2) (PubMed:22820328). Belongs to the DEAD box helicase family. CshB subfamily.