Compare 3D Structure of Two Penicillin Neutralizing Proteins




E. coli Penicillin Resistance Protein
B. cereus Penicillin Resistance Protein

Look at the E. coli enzyme in more detail , or look at the structure of penicillin.

These two enzymes both inactivate penicillin, but by different methods. The one one left is the same aenicillin acylase from E. coli that you can see in detail on another page. The enzyme on the right is anohter metallo beta lactamase but this one if from Bacillus cereus.
Reset E. coli enzyme and the B. cereus enzyme.

Rotate along the X-axis E. coli enzyme and B. cereus enzyme.

Rotate along the Y-axis E. coli enzyme and B. cereus enzyme.

Look at the subunit composition E. coli enzyme and B. cereus enzyme.

As you can see, these two bacteria have evolved different mechanisms to resist penicillin.

What does that suggest to you about the selection pressures for antibiotic resistance and the potential to produce compounds that cannot be resisted by bacteria?