FIGURE 2.

Crystal structure of YtfQ. a, schematic of the structure of YtfQ colored with rainbow coloring from the N terminus (blue) to the C terminus (yellow). The galactofuranose is shown in a stick representation. The single disulfide bond joining residues Cys-129 and Cys-193 is indicated in dark blue. b, topology diagram of YtfQ. The N-terminal domain is in white and the C-terminal domain in gray. Circles represent α-helices, triangles represent β-strands, and unfilled ovals are 3₁₀ helices. The double line from β6 indicates the position of the disulfide bond. c, structure of galactofuranose modeled into electron density contoured at 1.5 σ.