Cellulose is an essential plant cell wall component and represents the most abundant biopolymer on Earth. Supramolecular cellulose synthase complexes organize multiple linear glucose polymers into microfibrils as load-bearing components. We determined structure of a poplar CesA homotrimer that suggests molecular basis for microfibril formation. This complex, stabilized by cytosolic plant-conserved regions helical exchange within transmembrane segments, forms three channels occupied nascent...

Significance Cellulose is an abundant natural polymer synthesized primarily by vascular plants in which it forms the load-bearing component of cell wall. It a linear glucose molecules membrane-embedded cellulose synthases that couple synthesis with its secretion across plasma membrane. Plants express multiple synthase isoforms are organized into large macromolecular assemblies varying composition likely responsible for aligning strands microfibrils. Here we show recombinantly expressed and...

We describe the heterologous expression and characterization of a 407-residue single-domain glycosyl hydrolase family 18 chitinase (SpChiD) from Gram-negative Serratia proteamaculans 568 that has unprecedented catalytic properties. SpChiD was optimally active at pH 6.0 40 °C, where it showed K(m) 83 mg ml(-1), k(cat) 3.9 × 10(2) h(-1), k(cat)/K(m) 4.7 h mg(-1) ml(-1) on colloidal chitin. On chitobiose, K(m), k(cat), were 203 μM, 1.3 0.62 h(-1) μM(-1), respectively. Hydrolytic activity...

Cellulose, the major component of plant cell walls, can be converted to bioethanol and is thus highly studied. In plants, cellulose produced by synthase, a processive family-2 glycosyltransferase. individual β-1,4-glucan chains polymerized CesA are assembled into microfibrils that frequently bundled macrofibrils. An in vitro system which synthesized fibrils would facilitate detailed study this process. Here, we report heterologous expression partial purification His-tagged CesA5 from...

Plant cell walls contain a meshwork of cellulose fibers embedded into matrix other carbohydrate and non-carbohydrate-based biopolymers. This composite material exhibits extraordinary properties, from stretchable pliable boundaries to solid protective shells. Cellulose, linear glucose polymer, is synthesized secreted across the plasma membrane by synthase (CesA), which plants express multiple isoforms. Different subsets CesA isoforms are necessary for primary secondary wall biogenesis. Here,...

Genome sequence of Serratia proteamaculans 568 revealed the presence three family 33 chitin binding proteins (CBPs). The Sp CBPs (Sp CBP21, CBP28 and CBP50) were heterologously expressed purified. CBP21 CBP50 showed preference to β-chitin, while did not bind cellulose substrates. Both synergistic with four chitinases from S. ChiA, ChiB, ChiC ChiD) in degradation α- especially external electron donor (reduced glutathione). ChiD benefited most or on α-chitin, ChiB had major advantage these...

We describe the improvement of transglycosylation (TG) by chitinase D from Serratia proteamaculans (SpChiD). The SpChiD produced a smaller quantity TG products for up to 90 min with 2 mm chitotetraose as substrate and subsequently only hydrolytic products. Of five residues targeted at catalytic center, E159D resulted in substantial loss both activities. Y160A product profile similar rapid turnover slightly increased activity. rest three mutants, M226A, Y228A, R284A, displayed improved...

Mixed-linkage (1,3;1,4)-β-glucans, which are widely distributed in cell walls of the grasses, linear glucose polymers containing predominantly (1,4)-β-linked glucosyl units interspersed with single (1,3)-β-linked units. Their distribution cereal grains and unique structures important determinants dietary fibers that beneficial to human health. We demonstrate barley cellulose synthase-like CslF6 enzyme is sufficient synthesize a high-molecular weight (1,3;1,4)-β-glucan vitro. Biochemical...

HrpZ—a harpin from Pseudomonas syringae—is a highly thermostable protein that exhibits multifunctional abilities e.g., it elicits hypersensitive response (HR), enhances plant growth, acts as virulence factor, and forms pores in plasma membranes well artificial membranes. However, the molecular mechanism of its biological activity high thermal stability remained poorly understood. HR inducing non-overlapping short deletion mutants harpins put further constraints on ability to establish...

Abstract In land plants and algae, cellulose is important for strengthening cell walls preventing breakage due to physical forces. Though our understanding of production by synthases (CESAs) has seen significant advances several plant bacterial species, functional characterization this fundamental protein absent in red algae. Here we identify CESA gene candidates the calcifying alga Calliarthron tuberculosum using sequence similarity-based approaches, elucidate their phylogenetic...

Abstract Plant cell walls contain a meshwork of cellulose fibers embedded into matrix other carbohydrate and non-carbohydrate-based biopolymers. This composite material exhibits extraordinary properties, from stretchable pliable boundaries to solid protective shells. Cellulose, linear glucose polymer, is synthesized secreted across the plasma membrane by synthase (CesA). Plants express several CesA isoforms, with different subsets necessary for primary secondary wall biogenesis. The produced...

Plant cell walls contain a meshwork of cellulose fibers embedded into matrix other carbohydrate and non-carbohydrate-based biopolymers. This composite material exhibits extraordinary properties, from stretchable pliable boundaries to solid protective shells. Cellulose, linear glucose polymer, is synthesized secreted across the plasma membrane by synthase (CesA). Plants express several CesA isoforms, with different subsets necessary for primary secondary wall biogenesis. The produced chains...

Plant cell walls contain a meshwork of cellulose fibers embedded into matrix other carbohydrate and non-carbohydrate-based biopolymers. This composite material exhibits extraordinary properties, from stretchable pliable boundaries to solid protective shells. Cellulose, linear glucose polymer, is synthesized secreted across the plasma membrane by synthase (CesA). Plants express several CesA isoforms, with different subsets necessary for primary secondary wall biogenesis. The produced chains...