Table 3. Comparison of the number of van der Waals contacts and hydrogen bonds (the distance cutoff between non-H atoms is ≤3.2 Å) between the ligand (cocaine or benzoylecgonine) and the Fab in various complex structures.

The numbers of water molecules mediating hydrogen bonds between the ligand and the Fab are included in a separate column.

Fab complex	No. of contacts (≤4.0 Å)	No. of hydrogen bonds	No. of water molecules mediating hydrogen bonds
h2E2 (benzoylecgonine; this study)	66	0	1
PDB entry 1qyg (benzoylecgonine; Pozharski et al., 2005 ▸)	103	2	2
PDB entry 1q72 (cocaine; Pozharski et al., 2005 ▸)	93	0	1
PDB entry 1i7z (cocaine; Larsen et al., 2001 ▸)	68	0	1