Table 2. Conserved sequence motifs in penicillin-binding proteins and β-lactamases.

The conserved sequence motifs found within the αβα β-lactamase fold occur in penicillin-binding proteins and multiple classes of β-lactamases. The motifs occur in different secondary structures in the same relative positions across different proteins. Fvan-cmp shares two of the three conserved motifs but lacks the third motif. The residues are identified by their sequence for clarity.

Conserved sequence		Location within fold	Fvan-cmp sequence
1	S-X-X-K	α-Helix	S343-V-S-K346
2	Y/S-X-N†	Active site facing loop, before α-helix	Y447-S-N449
3	K-T-G	Terminal β-strand on β-sheet	n/a

^†Class A β-lactamases and penicillin-binding proteins contain a serine while class C β-­lactamases contain a tyrosine at the first position of this motif.