Krishna Mohan Padmanabha Das, Shruti Barve, Sampali Banerjee, Suman Bandyopadhyay and Sriram Padmanabhan
Cherry tag, a red polypeptide of the heme binding part of cytochrome is used to attain high levels of soluble protein expression in E. coli. A novel heat stability conferring property of this tag was observed and studied for constructs of two soluble fusions especially Cherry-Granulocyte colony stimulating factor (GCSF) and Cherry- Staphylokinase (SAK). Heat incubation of these fusion proteins at 70°C for 20 minutes culminated in specific denaturation and precipitation of E. coli proteins excluding the fusion proteins. Both the heat treated fusion proteins were found to be functionally active. Thus Cherry fusion tag could be used as a cost-efficient tool in purification of proteins by imparting heat stability.