Takara's pCold ProS2 DNA is a cold shock expression vector that includes Protein S derived from a Gram-negative myxobacteria Myxococcus xanthus as a solubilization tag. Protein S, (173 aa) is very stable soluble protein present in the spore surface coat of Myxococcus xanthus. Fusing a target gene encoding a protein of interest with the ProS2 Tag, found in pCold ProS2 DNA may induce the stability and solubility of the fusion protein.
The pCold ProS2 DNA Vector consists of the cspA promoter plus additional downstream sequences including a 5' untranslated region (5' UTR), a translation
enhancing element (TEE), a His-Tag sequence, ProS2 Tag, and a multicloning site (MCS). A lac operator is inserted downstream of the cspA promoter to ensure
strict regulation of expression. Additionally, recognition sites for HRV 3C Protease, Thrombin, and Factor Xa are located between ProS2 Tag and the Multiple Cloning Site (MCS) and function to facilitate tag removal from the expressed fusion protein. Most E. coli strains can serve as expression hosts. The pCold ProS2 DNA Vector provides cold shock technology for high yield protein expression to facilitate correct protein folding, thus enabling efficient soluble protein production for otherwise intractable target proteins.