FIGURE 3.

COBRA competition assay with crystalline cellulose (Avicel) and individual glucan chains (cellohexaose). Pulldown assays of full-length COBRA and Avicel were performed with increasing concentrations of cellohexaose. Without cellohexaose, COBRA binds to Avicel. 1 μm Cellohexaose was enough to prevent a significant fraction of COBRA from binding to Avicel, with 3 μm cellohexaose, which represented a binding association constant for COBRA of 3.2 μm. In 30 μm cellohexaose, a 10-fold increase over the K_D, COBRA could not be detected in the fraction bound to Avicel.