A periplasmic glutamate/aspartate binding protein from Shigella flexneri:: Gene cloning, over-expression, purification and preliminary crystallographic studies of the recombinant protein

Periplasmic substrate binding proteins (PSBPs) are essential components of the bacterial periplasmic transport system, which transports a wide variety of nutrients from the periplasmic space to the cytoplasm. The glutamate/aspartate binding protein SfGlu/AspBP is a unique PSBP consisting of 279 amino acid residues. The SfGlu/AspBP gene was cloned, over-expressed, and purified by immobilized metal ion affinity chromatography and size-exclusion chromatography, The recombinant protein SfGlu/AspBP has been crystallized by the hanging-drop vapor-diffusion method and its Xray diffraction data were collected at an atomic resolution of 1.15 angstrom. The crystals belong to the space group P2(1) with unit cell parameters: a=48.41 angstrom, b=68.18 angstrom, c=80.21 angstrom and beta = 98.78 degrees. There are two molecules per asymmetric unit.