FIGURE 2.

The DocI modules in the DocI·CohI₉–X DocII·CohII structure display a single orientation opposite to what has been seen previously. A displays an alignment of the four CohI₉·DocI from the DocI·CohI₉–X DocII·CohII crystal structure (Protein Data Bank code 4FL4). The CohI module is shown in yellow, and the DocI modules from molecules 1, 2, 3, and 4 are red, green, blue, and orange, respectively. B shows a representative CohI₉·DocI orientation from the DocI·CohI₉–X DocII·CohII crystal structure with the CohI₉ and DocI modules shown in yellow and orange, respectively. C and D show the Xyn10B DocI·CohI (Protein Data Bank code 1OHZ) and the Xyn10B S54A/T46 DocI·CohI (2CCL) structures, respectively (14, 15). In both, the CohI modules are yellow. The wild-type DocI module is red, and the S54A/T46 mutant is shown in brown.