Fig. 5: Unusual conformation of delafloxacin in the 2.0 Å complex of S. pneumoniae topo IV with V18 DNA (PDB ID: 8QMB) featuring out-of-plane N-1 aromatic and C-8 chlorine substituents.
From: Structural basis of topoisomerase targeting by delafloxacin
a, b Opposing views of the delafloxacin molecule with its chelated magnesium ion and associated waters with the electron density from the (Fo–Fc) map denoted by a mesh contoured at 1.5σ (limited to 2.3 Å range). The chelated magnesium ion is shown in purple and bound water shown in red. a, b show views perpendicular and parallel to the bicyclic quinolone ring, respectively. c Representation in full van der Waal radius of the delafloxacin molecule from the 2.0 Å topo IV X-ray crystal structure, indicating that the large electronegative Cl atom (shown in green) interacts directly to facilitate/stabilise tilting of the N1 heteroaromatic ring (dark grey).
