E. coli ENR and B. napus ENR have very similar structures, with a high sequence identity. The main notable difference between ENR in the two species is a flexible region on the E. coli isoform. This domain cannot be resolved in E. coli, but can be in B. napus, potentially due to additional hydrogen bonds that are present in B. napus.
The function of the two enzymes in very similar, due to their high sequence identity.