The polysaccharide structure and dynamics in the primary cell wall of the model grass Brachypodium distachyon are investigated for the first time using solid-state nuclear magnetic resonance (NMR). While both grass and non-grass cell walls contain cellulose as the main structural scaffold, the former contains xylan with arabinose and glucuronic acid substitutions as the main hemicellulose, with...

Auxiliary activity 9 (AA9) lytic polysaccharide monooxygenases (LPMOs) are copper-dependent oxidoreductases that use O2 or H2O2 to perform oxidative cleavage of cellulose in the presence an electron donor. Combined with cellulases, they can assist a more efficient cellulose. AA9 LPMOs have therefore attracted considerable attention recent years for biotechnological applications. Here, native LP...

The structural role of pectins in plant primary cell walls is not yet well understood because of the complex and disordered nature of the cell wall polymers. We recently introduced multidimensional solid-state nuclear magnetic resonance spectroscopy to characterize the spatial proximities of wall polysaccharides. The data showed extensive cross peaks between pectins and cellulose in the primary...

The cellulosome is a supramolecular multienzyme complex comprised of a wide variety of polysaccharide-degrading enzymes and scaffold proteins. The cellulosomal enzymes that bind to the scaffold proteins synergistically degrade crystalline cellulose. Here, we report in vitro reconstitution of the Clostridium thermocellum cellulosome from 40 cellulosomal components and the full-length scaffoldin ...

Plant cell walls are complex composites largely consisting of carbohydrate-based polymers, and are generally divided into primary and secondary walls based on content and characteristics. Cellulose microfibrils constitute a major component of both primary and secondary cell walls and are synthesized at the plasma membrane by cellulose synthase (CESA) complexes. Several studies in Arabidopsis ha...

Cellulose is the most familiar and most abundant strong biopolymer, but the reasons for its outstanding mechanical performance are not well understood. Each glucose unit in a cellulose chain is joined to the next by a covalent C-O-C linkage flanked by two hydrogen bonds. This geometry suggests some form of cooperativity between covalent and hydrogen bonding. Using infrared spectroscopy and X-ra...

BACKGROUND Lytic polysaccharide monooxygenases (LPMOs) are a class of powerful oxidative enzymes that have revolutionized our understanding of lignocellulose degradation. Fungal LPMOs of the AA9 family target cellulose and hemicelluloses. AA9 LPMO-coding genes have been identified across a wide range of fungal saprotrophs (Ascomycotina, Basidiomycotina, etc.), but so far they have not been foun...

A novel gene, eglC, encoding an endoglucanase, was cloned from Aspergillus niger. Transcription of eglC is regulated by XlnR, a transcriptional activator that controls the degradation of polysaccharides in plant cell walls. EglC is an 858-amino-acid protein and contains a conserved C-terminal cellulose-binding domain. EglC can be classified in glycoside hydrolase family 74. No homology to any o...

Polysaccharide analyses of mutants link several of the glycosyltransferases encoded by the 10 CesA genes of Arabidopsis to cellulose synthesis. Features of those mutant phenotypes point to particular genes depositing cellulose predominantly in either primary or secondary walls. We used transformation with antisense constructs to investigate the functions of CesA2 (AthA) and CesA3 (AthB), genes ...