Bacterial Cold Shock Proteins - the Molecular Chaperones for Multiple Stress Tolerance

Bacteria encounter different changing environments but resist the environmental changes by developing an array of mechanisms which protect them from adverse conditions. During cold conditions, fluidity of cell membranes decreases, and this results in lowering of active transport and protein secretion [1]. Further, all the molecular mechanisms gets impaired due to stabilization of secondary structures of DNA, RNA, and proteins [2]. RNA binding proteins (RNA chaperones) are ubiquitous and found in all living organisms and help to resolve the misfolded RNA structures under abiotic stress conditions. During rapid drop in temperatures, cold-induced proteins (Cips) are produced to protect the cells. With an increase in the cold conditions, the production of Cips also increases [3]. Different types of Cips like cold shock protein (Csp) family, RNA helicase csdA, exoribonucleases, PNPase and RNaseR, initiation factors 2a and 2b, NusA, and RecA [4-7] have been identified in Escherichia coli (E. coli). The Csps are one of the major Cips produced under cold conditions mainly in bacteria [4,8].