Cloning, expression, purification, crystallization and preliminary X-ray diffraction analysis of SAICAR synthase from Streptococcus suis serotype 2

Phosphoribosylaminoimidazole-succinocarboxamide synthase (SAICAR syn­thase) plays an essential role in the de novo biosynthesis of purine nucleotides. In this study, the SAICAR synthase from Streptococcus suis was cloned and overexpressed in Escherichia coli. The subsequent product was purified and crystallized using the hanging-drop vapour-diffusion method. The crystals diffracted to 2.8 Å resolution and belonged to space group P2, with unit-cell parameters a = 70.2, b = 52.2, c = 153.9 Å, β = 102.8°.