FIG. 4.

Interactions between E. coli PDF and VRC4307. (A) Schematic representation of key interactions between PDF and VRC4307. (B) Interactions of the hydroxamic acid with the active-site metal. Although the ligand coordination geometry is a distorted trigonal bipyramid, the fifth ligand, the carbonyl oxygen, is positioned too far from the Ni²⁺ atom for optimal interactions with three complexes (2.7, 2.7, and 3.0 Å). Solid lines indicate proposed interactions; the potential fifth ligand interaction is shown as broken lines.