Structure and Interactions of Plant Cell-Wall Polysaccharides by Two- and Three-Dimensional Magic-Angle-Spinning Solid-State NMR

TitleStructure and Interactions of Plant Cell-Wall Polysaccharides by Two- and Three-Dimensional Magic-Angle-Spinning Solid-State NMR
Publication TypeJournal Article
Year of Publication2011
AuthorsDick-Perez M, Zhang YA, Hayes J, Salazar A, Zabotina OA, Hong M
Journal TitleBiochemistry
Volume50
Pages989-1000
Date Published02
Type of ArticleArticle
ISBN Number0006-2960
Accession NumberISI:000287049500009
KeywordsARABIDOPSIS-THALIANA, cellulose, chemical-shift, cultured sycamore cells, fruits, macromolecular components, nuclear-magnetic-resonance, pectic, polysaccharides, prickly pear, spectroscopy, xyloglucan
Abstract

The polysaccharide-rich cell walls (CWs) of plants perform essential functions such as maintaining tensile strength and allowing plant growth. Using two- and three-dimensional magic-angle-spinning (MAS) solid-state NMR and uniformly C-13-labeled Arabidopsis thaliana, we have assigned the resonances of the major polysaccharides in the intact and insoluble primary CW and determined the intermolecular contacts and dynamics of cellulose, hemicelluloses, and pectins. Cellulose microfibrils showed extensive interactions with pectins, while the main hemicellulose, xyloglucan, exhibited few cellulose cross-peaks, suggesting limited entrapment in the microfibrils rather than extensive surface coating. Site-resolved C-13 T-1 and H-1 T-1p relaxation times indicate that the entrapped xyloglucan has motional properties that are intermediate between the rigid cellulose and the dynamic pectins. Xyloglucan absence in a triple knockout mutant caused the polysaccharides to undergo much faster motions than in the wild-type CW. These results suggest that load bearing in plant CWs is accomplished by a single network of all three types of polysaccharides instead of a cellulose xyloglucan network, thus revising the existing paradigm of CW structure. The extensive pectin-cellulose interaction suggests a central role for pectins in maintaining the structure and function of plant-CWs. This study demonstrates the power of multidimensional MAS NMR for molecular level investigation of the structure and dynamics of complex and energy-rich plant materials.

URL<Go to ISI>://000287049500009
DOI10.1021/bi101795q
Alternate JournalBiochemistry