Heat stable ssDNA/RNA-binding activity of a wheat cold shock domain protein

The cold-induced wheat WCSP1 protein belongs to the cold shock domain (CSD) protein family. In prokaryotes and eukaryotes, the CSD functions as a nucleic acid-binding domain. Here, we demonstrated that purified recombinant WCSP1 is boiling soluble and binds ss/dsDNA and mRNA. Furthermore, boiled-WCSP1 retained its characteristic nucleic acid-binding activity. A WCSP1 deletion mutant, containing only a CSD, lost ssDNA/RNA-binding activity; while a mutant containing the CSD and the first glycine-rich region (GR) displayed the activity. These data indicated that the first GR of WCSP1 is necessary for the binding activity but is not for the heat stability of the protein.