Purification, crystallization and preliminary crystallographic characterization of the α2,6-sialyltransferase from Photobacterium sp. JT-ISH-224

Sialyltransferases transfer sialic acid from cytidine-5-monophospho-N-acetylneuraminic acid (CMP-NeuAc) to the nonreducing termini of the oligosaccharyl structures of various glycoproteins and glycolipids. The newly cloned alpha2,6-sialyltransferase from Photobacterium sp. JT-ISH-224 (from the Vibrionaceae family) is composed of two domains: an unknown N-terminal domain and a catalytic C-terminal domain which shares significant homology with the Pasteurella multocida multifunctional sialyltransferase. The putative mature form of JT-ISH-224 alpha2,6-sialyltransferase was overproduced in Escherichia coli, purified and crystallized using the hanging-drop vapour-diffusion method at 293 K. The crystal belonged to space group P3(1)21 or P3(2)21, with unit-cell parameters a = b = 90.29, c = 204.33 A. X-ray diffraction data were collected to 2.5 A resolution.