View source for Im4

Im4 is an immunity protein that is produced by ''E. coli'' at the same time as [[Colicin E4]] to protect itself from the [[Colicin]]'s cytotoxic [[16s rRNase activity]]. It binds to the C domain and inhibits its enzymatic activity, to protect the colicinogenic cell from death. It is later released from this domain when the colicin binds [[BtuB]], the receptor on the target cell.