FIG. 3.

Structure of the polypeptide linkers between the 3C and 3D domains of the two molecules of 3CD in the asymmetric unit. An omit map contoured at 1.4σ shows weak density in the linker regions, though the overall path of the backbone is clear. The linker regions of the two 3CD molecules in the asymmetric unit differ in structure, confirming that the linker is only weakly ordered. The two linkers are shown in similar orientations, with the 3C domain on the left and the 3D domain on the right.