Fig. 4.

EXPB1 activities. (A) Hydrolytic activity of EXPB1 against various wall polysaccharides. Data are means ± SEM (n = 3). The positive control with arabinoxylan is a crude extract of maize pollen containing endoxylanase activity (69). (B) Maize cell walls bind EXPB1. After incubation of EXPB1 with or without cell wall, protein remaining in the supernatant was analyzed by SDS/PAGE and stained with SYPRO Ruby. (C) EXPB1 binding to isolated polysaccharides immobilized onto nitrocellulose membrane. NC, nitrocellulose membrane alone; G, β-(1→3),(1→4)-d-glucan; GM, glucomannan; XG, xyloglucan; OX, oat xylan; BX, birch xylan. Data are means ± SEM (n = 3). (D) Swelling of maize cell walls after 48 h of incubation with or without EXPB1. Methods were as described for the binding studies.