FIG. 5.

Comparisons with the previously published θ structure (1DU2). Ribbon diagrams are displayed for residues 11 to 65 of the structure determined in this work (a, blue) and the previously reported structure 1DU2 (28) (b, yellow). Residues that were unassigned in the previous study are cyan in panel a and red in panel b. The structures in panels a and b are in approximately the same orientation as in panel c. In making the overlay in panel c, only residues 11 to 19 of the two structures were aligned. The arrows indicate the direction of the primary sequence. Note that W51, shown as a stick figure, is in a similar position, although helix 3 of 1DU2 runs in the opposite direction relative to helix 2. The insufficient assignment data in the 1DU2 structure led to an antiparallel orientation of α1 and α3, compared with the roughly parallel alignment in the determined structure.