FIGURE 1.

The crystal structures of human β4GalT7 in the open (A) and the closed (B) conformation. A manganese ion and a UDP molecule are shown as a purple sphere and a green-and-orange stick figure, respectively. In the open conformation (A), the electron density was visible up to His²⁵⁹, and the clear electron density appeared again at Gly²⁸⁵ (blue sphere). The His²⁵⁷-X-His²⁵⁹ motif, Trp²²⁴, and the N and C termini are indicated. A disulfide bond is shown in a ball-and-stick format, with the yellow spheres indicating sulfur atoms. In B, the long loop region, residues 260–285, invisible in the open conformation, is highlighted in red.