Initiating a crystallographic study of ­UDP-­galactopyranose mutase from Escherichia coli

UDP-galactopyranose mutase, the enzyme responsible for the conversion of UDP-galactopyranose to UDP-galactofuranose, has been crystallized in a form suitable for X-ray diffraction studies. UDP-galactofuranose is a key component of mycobacterial cell walls. Crystals of both the native protein and a selenomethionine variant have been grown by the vapour-diffusion method in hanging drops, and diffract to beyond 3.0 Å using synchrotron radiation. Equilibration was against a solution of 20%(w/v) polyethylene glycol (4K), 12%(v/v) 2-­propanol, 0.1 M HEPES pH 7.6 at 293.5 K. Crystals grow as thin plates of dimensions 0.4 × 0.2 × ∼0.02 mm. They are orthorhombic, space group P2₁, with unit-cell dimensions a = 71.12, b = 58.42, c = 96.38 Å, β = 96.38°. 92% (native) and 94% (selenomethionine) complete data sets have been recorded to 2.9 Å (R_merge = 5.0%) and 3.0 Å (R_merge = 6.9%), respectively. The Matthews coefficient is 2.35 ų Da⁻¹ for a dimer in the asymmetric unit, the solvent content being 47%. Diffraction data have also been recorded on a putative platinum derivative to 3.5 Å.