Figure 5. Expansins net charge depends on pH, and ionic strength determines their interaction with cellulose.

(a) Theoretical net charge of the proteins at different pH values: full circles correspond to BsEXLX1 and open squares to PcExl1. (b) Ionic strength effect on binding to Avicel was determined experimentally, by incubating 1 mg of substrate with 5 µg of expansins (BsEXLX1, full circles; PcExl1, open squares) for one hour. Results are the arithmetic mean and standard deviations of three independent experiments.