title: Role of (1,3)(1,4)-β-glucan in cell walls: interaction with cellulose.
abstract: (1,3)(1,4)-β-D-Glucan (mixed-linkage glucan or MLG), a characteristic hemicellulose in primary cell walls of grasses, was investigated to determine both its role in cell walls and its interaction with cellulose and other cell wall polysaccharides in vitro. Binding isotherms showed that MLG adsorption onto microcrystalline cellulose is slow, irreversible, and temperature-dependent. Measurements using quartz crystal microbalance with dissipation monitoring showed that MLG adsorbed irreversibly onto amorphous regenerated cellulose, forming a thick hydrogel. Oligosaccharide profiling using endo-(1,3)(1,4)-β-glucanase indicated that there was no difference in the frequency and distribution of (1,3) and (1,4) links in bound and unbound MLG. The binding of MLG to cellulose was reduced if the cellulose samples were first treated with certain cell wall polysaccharides, such as xyloglucan and glucuronoarabinoxylan. The tethering function of MLG in cell walls was tested by applying endo-(1,3)(1,4)-β-glucanase to wall samples in a constant force extensometer. Cell wall extension was not induced, which indicates that enzyme-accessible MLG does not tether cellulose fibrils into a load-bearing network.
authors.affiliation: Department of Biology, Pennsylvania State University , University Park, Pennsylvania 16803, United States.
authors.forename: Sarah N
authors.initials: SN
authors.lastname: Kiemle
authors.forename: Xiao
authors.initials: X
authors.lastname: Zhang
authors.forename: Alan R
authors.initials: AR
authors.lastname: Esker
authors.forename: Guillermo
authors.initials: G
authors.lastname: Toriz
authors.forename: Paul
authors.initials: P
authors.lastname: Gatenholm
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Cosgrove
mesh_terms: D000327:Adsorption; D002473:Cell Wall / Q000737:chemistry* / Q000378:metabolism; D002482:Cellulose / Q000737:chemistry* / Q000378:metabolism; D005936:Glucans / Q000737:chemistry* / Q000378:metabolism*; D020100:Hydrogels / Q000138:chemical synthesis / Q000737:chemistry; D010316:Particle Size; D058525:Quartz Crystal Microbalance Techniques; D013499:Surface Properties; D014908:Triticum / Q000737:chemistry* / Q000166:cytology; D003313:Zea mays / Q000737:chemistry* / Q000166:cytology
chemical_list: D005936:Glucans; D020100:Hydrogels; D002482:Cellulose