Expression, purification and preliminary X-ray crystallographic analysis of PsaA, a putative metal-transporter protein of Streptococcus pneumoniae

The putative metal-transporter protein PsaA of Streptococcus pneumoniae is of potential interest both as a vaccine and also as a drug target. The overexpression of the protein in E. coti, and its subsequent purification and crystallization are described. The crystals are rectangular rods and diffract to beyond 2.7 Angstrom resolution. The crystal space group is P2(1)2(1)2(1) with unit-cell dimensions a = 59.9, b = 66.5 and c = 69.9 Angstrom.