FIGURE 4.

Overlay of the PenA (colored) and PenI (gray) active sites highlighting the following major motifs: ⁷⁰SXXK⁷³ motif (green), ¹³⁰SDN¹³² loop (orange), ²³⁴KTG²³⁶ motif (yellow), B3 β-strand (yellow), 102–110 loop (blue), and Ω loop (red), and the approximate binding pocket (gray oval) for β-lactams and β-lactamase inhibitors.