中国生物工程杂志

Era is a highly conserved GTPase essential for bacterial growth. yggG gene was identified to encod a Era-binding protein when Using a digoxigenin-labeled Era protein to screen a phage expression library of Escherichia coli genomic DNA. Subsequent study showed the regulation of yggG gene was associated with environment stress, indicating yggG expression products involved in the stress regulation of bacteria responding to environment changes. In this study, To confirm the interactions between Era and YggG proteins when overexpressed, E. coli cells were exposed to a double promoter plasmid, pDH2-YggG-Ptac-Era that was induced to express the Era and YggG proteins by different induction methods. Immunoprecipitation of cell lysates to detect YggG/Era complexes. Then expression and purification of GST fusion truncated peptide of Era N terminus, Era C-terminus and Era C-terminus and linker. Identified the interaction of YggG and different Era truncated peptides by GST Pull-down. Our results showed that YggG/Era complexes existed in the cell lysates over-expressed YggG and Era, which was not able to detect in cells over expressed YggG or Era only. GST pull-down assay showed GST fused Era protein, GST fused Era N-terminus peptide and GST fused C-terminus peptide could pull-down YggG protein. The binding activity of YggG to Era C-terminus was same to Era, which was more strong than that to Era N-terminus. The results indicated that YggG is a Era-binding protein in E. coli, and the binding activity of YggG to Era N-terminus and C-terminus are difference.