FIG. 6.

Binding of recombinant proteins derived from CttA to crystalline cellulose. For the assay, the recombinant products were incubated with Avicel or cotton, as indicated, and then washed, and the bound material was recovered by heating in Laemmli buffer. CBPs were separated by SDS-PAGE and blotted onto polyvinylidene difluoride membranes, and polyhistidine-tagged proteins were revealed by chemiluminescence using Ni-conjugated HRP. (A) Binding of the recombinant product His₆-CttA (46 kDa) and its proteolytic derivative to Avicel. (B) Binding of the double-polyhistidine-tagged product 2X-His₆-CttA and its proteolytic derivatives to Avicel and cotton and inhibition of binding by the addition of 0.2% HEC (hydroxyethyl cellulose). (C) Binding of recombinant 32-kDa and 25-kDa derivatives—CttA1 and CttA2, respectively—to Avicel and inhibition of their binding by the addition of 0.2% HEC.