Fig. 4

The NaD1–PA complex contains 14 PA molecules bound in identical NaD1-dimer binding sites. a The 20-meric complex (cartoon representation with gray transparent surface rendering, with the two 3-dimer arcs in pink, and the central 4-dimer arc in blue) harboring 14 bound PA molecules (shown as spheres with carbon in green, oxygen in red, phosphorus in orange), as viewed from the bottom. b A schematic of the three constituent arcs of the 20-meric complex. Each dimer engages one or two PA molecules (red circles), with the full complex binding 14 PA molecules in total. c A representative NaD1–PA binding site, with PA (shown as sticks) located within the cationic grip. One monomer of the dimer (orange) engages the PA phosphate head group through Ser35, Ile37, Leu38, and Arg40, while Arg39 and Lys36 (pink) of a single chain from a neighboring dimer are recruited through a hydrogen bond network involving three water molecules that are conserved in each binding site. d A schematic of how two dimers from c cooperatively bind two PA molecules