CspA encodes a major cold shock protein in Himalayan psychrotolerant Pseudomonas strains.

Abstract

The major cold-shock protein (CspA) encoding gene cspA were detected in three Himalayan psychrotrophic Pseudomonad strains, by PCR amplification. Partial sequencing of three Pseudomonas strains cspA gene and BLAST search confirmed the high similarity with putative bacterial cspA gene and bacterial CspA protein. Bioinformatics analysis of these partial CspA amino acid sequences showed presence of putative conserved region for DNA/RNA-binding motifs RNP-1 and RNP-2. Protein homologies of all three bacterial CspA proteins belong to S1 like protein (Ribosomal protein S1-like RNA-binding domain). Presence of cspA gene and its high similarity with Bacillus cereus group demonstrating uniqueness of cspA gene in these Pseudomonas strains and suggesting strong evolutionary relationship between these two groups to survive in cold environments. Probable CspA protein expression levels were checked after cold shock (28°C to 4°C) and cold acclimation (4°C and 15°C) experiment. SDS-PAGE analysis revealed a small protein of approximate size of 7.5 kDa was expressed after cold shock (28°C to 4°C) and continuously over-expressed with the incubation time at cold temperature (4°C). Therefore it was predicted this protein would be product of cspA gene and suggesting this protein aids survival in Himalayan environments.