Cloning, expression, crystallization and preliminary X-ray diffraction studies of staphylococcal superantigen-like protein 1 (SSL1)
Staphylococcus aureusproduces a family of exotoxins which are structural homologues of superantigens and thus are called staphylococcal superantigen-like proteins (SSLs). Amongst the 14 SSL genes,ssl1(SAOUHSC_00383) has been cloned in the pQE30 expression vector, overexpressed inEscherichia coliM15 (pREP4) cells and the protein purified to homogeneity. The protein was crystallized using 6% Tacsimate pH 6.0, 0.1 MMES pH 6.0, 25%(w/v) polyethylene glycol 3350, 100 mMNDSB 256 at 298 K by the sitting-drop vapour-diffusion method. The crystals belonged to space groupP21, with unit-cell parametersa= 77.9,b= 70.5,c= 126.5 Å, β = 106.2°. X-ray diffraction data were collected and processed to a maximum resolution of 2.5 Å. The crystal contains six molecules in the asymmetric unit.