Crystallization and preliminary X-ray crystallographic analysis of Z-ring-associated protein (ZapD) from Escherichia coli

Bacterial cytokinesis is accomplished by the Z-ring, which is a polymeric structure that includes the tubulin homologue FtsZ at the division site. ZapD, a Z-ring-associated protein, directly binds to FtsZ and stabilizes the polymerization of FtsZ to form a stable Z-ring during cytokinesis. Structural analysis of ZapD from Escherichia coli was performed to investigate the mechanism of ZapD-mediated FtsZ stabilization and polymerization. ZapD was crystallized using a reservoir solution consisting of 1.5 M lithium sulfate, 0.1 M HEPES pH 7.8, 2%(v/v) polyethylene glycol 400. X-ray diffraction data were collected to 2.95 Å resolution. The crystals belonged to the hexagonal space group P6₄, with unit-cell parameters a = b = 109.5, c = 106.7 Å, γ = 120.0°. Two monomers were present in the asymmetric unit, resulting in a crystal volume per protein mass (V_M) of 3.25 ų Da⁻¹ and a solvent content of 62.17%.