Fig. 2. Top: identification of the proteolytic cleavage fragments by Edman degradation. Possible cleavage positions in the EcoRII primary sequence were determined from the molecular weight of the fragments in SDS–polyacrylamide gels. Bottom: assignment of the proteolytic fragments to the EcoRII sequence. The amino acid sequences of the N-terminal fragments B and E start with the His₆ tag of the protein. The length of the bars represents the length of the EcoRII sequence (404 amino acids) and of the proteolytic fragments, respectively.