Preparation, crystallization and preliminary X-ray crystallographic studies of diadenosine tetraphosphate hydrolase from Shigella flexneri 2a

The 31.3 kDa Ap₄A hydrolase from Shigella flexneri 2a has been cloned, expressed and purified using an Escherichia coli expression system. Crystals of Ap₄A hydrolase have been obtained by the hanging-drop technique at 291 K using PEG 550 MME as precipitant. Diadenosine tetraphosphate (Ap₄A) hydrolase (EC 3.6.1.41) hydrolyzes Ap₄A symmetrically in prokaryotes. It plays a potential role in organisms by regulating the concentration of Ap₄A in vivo. To date, no three-dimensional structures of proteins with significant sequence homology to this protein have been determined. The 31.3 kDa Ap₄A hydrolase from Shigella flexneri 2a has been cloned, expressed and purified using an Escherichia coli expression system. Crystals of Ap₄A hydrolase have been obtained by the hanging-drop technique at 291 K using PEG 550 MME as precipitant. Ap₄A hydrolase crystals diffract X-rays to 3.26 Å and belong to space group P2₁, with unit-cell parameters a = 118.9, b = 54.6, c = 128.5 Å, β = 95.7°