Studies of the length of homogalacturonic regions in pectins by acid hydrolysis

Thibault, Jean‐François; Renard, Catherine M.G.C.; Axelos, Monique; Roger, Philippe; Crepeau, Marie-Jeanne

doi:10.1016/0008-6215(93)87019-o

Cited by 260 publications

(161 citation statements)

References 25 publications

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“…As we calculated above, a Hyp residue in APAP1 that bears a polysaccharide chain has an average of 13 GalA/GlcA residues and multiple xylan chains with an average length of seven to 11 xylosyl residues. This suggests that both the pectin and xylan domains of APAP1 are much shorter than those of native pectins (minimum of 70 to 100 GalA residues for HG regions) (Thibault et al, 1993) and xylans (up to 500 kD) (Porchia and Scheller, 2000). We hypothesize that APAP1 with longer pectin and arabinoxylan chains may exist in the cell walls and that such macromolecules are highly crosslinked and interwoven in the walls and thus cannot be released into the culture media.…”

Section: Discussionmentioning

confidence: 99%

“…The most abundant pectic polysaccharide, HG, is a linear homopolymer of 1→4 linked a-D-GalA residues that accounts for ;65% of pectin. HG may reach lengths of 100 residues or more (Thibault et al, 1993). The other major pectin, rhamnogalacturonan I (RG-I), comprises 20 to 35% of pectin and consists of a repetitive [-2-a-L-Rhap-1→4-a-D-GalAp-1-] disaccharide backbone with 20 to 80% of the rhamnosyl residues decorated by side chains of 1,5-arabinans, 1,4-galactans, and type I and type II arabinogalactans (Mohnen, 2008).…”

Section: Introductionmentioning

confidence: 99%

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An Arabidopsis Cell Wall Proteoglycan Consists of Pectin and Arabinoxylan Covalently Linked to an Arabinogalactan Protein

et al. 2013

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Plant cell walls are comprised largely of the polysaccharides cellulose, hemicellulose, and pectin, along with ;10% protein and up to 40% lignin. These wall polymers interact covalently and noncovalently to form the functional cell wall. Characterized cross-links in the wall include covalent linkages between wall glycoprotein extensins between rhamnogalacturonan II monomer domains and between polysaccharides and lignin phenolic residues. Here, we show that two isoforms of a purified Arabidopsis thaliana arabinogalactan protein (AGP) encoded by hydroxyproline-rich glycoprotein family protein gene At3g45230 are covalently attached to wall matrix hemicellulosic and pectic polysaccharides, with rhamnogalacturonan I (RG I)/homogalacturonan linked to the rhamnosyl residue in the arabinogalactan (AG) of the AGP and with arabinoxylan attached to either a rhamnosyl residue in the RG I domain or directly to an arabinosyl residue in the AG glycan domain. The existence of this wall structure, named ARABINOXYLAN PECTIN ARABINOGALACTAN PROTEIN1 (APAP1), is contrary to prevailing cell wall models that depict separate protein, pectin, and hemicellulose polysaccharide networks. The modified sugar composition and increased extractability of pectin and xylan immunoreactive epitopes in apap1 mutant aerial biomass support a role for the APAP1 proteoglycan in plant wall architecture and function.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

An Arabidopsis Cell Wall Proteoglycan Consists of Pectin and Arabinoxylan Covalently Linked to an Arabinogalactan Protein

et al. 2013

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“…temperatures with different degree of stability (GalA -GalA > GalA -Rha > neutral 323 sugar -neutral sugar) (Thibault, Renard, Axelos, Roger & Crépeau, 1993). 324…”

Section: Degradation Of Glycosidic Linkages Is Usually Observed At Lomentioning

confidence: 99%

Isolation and characterization of acetylated LM-pectins extracted from okra pods

2015

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48 49Pectin was isolated by aqueous extraction at pH 6.0 or 2.0 from okra 50 (Abelmoschus esculentus L.) pods. An isolation protocol was designed to extract 51 pectin and to study the influence of the extraction pH on their composition and 52 physicochemical properties. The extracted pectin was assessed using sugar 53 compositional analysis (neutral sugars, galacturonic acid, acetyl and methyl contents). 54FT-IR and NMR spectroscopy, size exclusion chromatography (SEC) and dilute 55 solution viscometry were also used to determine the macromolecular characteristics of 56 isolated pectin. The extraction protocols resulted in the isolation of pectin of high 57 purity as evidenced by their high total carbohydrate (70.0 -81.8%) and low protein 58 (4.3 -6.3%) contents. Samples contained between 46-56% galacturonic acid, had 59 broad molecular weight distributions, a low degree of methylation (40.0 and 24.6 %) 60 and high degree of acetylation (52.2 and 37.6 %). Neutral sugar analysis showed that 61 the pectin extracted at pH 6.0 contained more neutral sugars, particularly, galactose 62 (21.7 -25.7 mol%), rhamnose (10.1 -13.2 mol%) and arabinose (7.1 -7.3 mol%) 63 than that extracted at pH 2.0 indicating variations in fine structure. In addition, 64 molecular parameters of the isolated pectins, such as intrinsic viscosity (2.8 -4.4 dL 65 g -1 ), critical concentration (0.15 -0.45 dL g -1 ) and coil overlap parameter (0.66 -66 1.51), showed that extraction conditions resulted in pectin with different chain 67 morphology. The yield and physico-chemical characteristics of the extracted pectin 68 from okra pods were influenced by the extraction conditions. 69 70 71

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“…The blocks of PGA are separated by stretches in which (1 → 2)-␣ -L -rhamnose residues alternate with Gal p A (McNaught, 1997). Blocks of PGA may contain as many as 200 Gal p A units and span 100 nm (Thibault et al, 1993). Cations are necessary to neutralize PGA in solution and, as a consequence, influence its structure.…”

Section: Introductionmentioning

confidence: 99%

Structure of a Plant Cell Wall Fragment Complexed to Pectate Lyase C

et al. 1999

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The three-dimensional structure of a complex between the pectate lyase C (PelC) R218K mutant and a plant cell wall fragment has been determined by x-ray diffraction techniques to a resolution of 2.2 Å and refined to a crystallographic R factor of 18. Because the R218K PelC-galacturonopentaose complex represents an intermediate in the reaction pathway, the structure also reveals important details regarding the enzymatic mechanism. Notably, the results suggest that an arginine, which is invariant in the pectate lyase superfamily, is the amino acid that initiates proton abstraction during the ␤ elimination cleavage of polygalacturonic acid. INTRODUCTIONPectate lyases are depolymerizing enzymes that degrade plant cell walls, causing tissue maceration and death. The enzymes normally are secreted by phytopathogenic organisms and are known to be the primary virulence agents in soft rot diseases caused by Erwinia spp (Collmer and Keen, 1986;Kotoujansky, 1987;Barras et al., 1994). In the latter organisms, the enzymes exist as multiple, independently regulated isozymes that share amino acid sequence identity ranging from 27 to 80%.Pectate lyases share sequence similarities with fungal pectin lyases, plant pollen proteins, and plant style proteins (Henrissat et al., 1996). The three-dimensional structures of five members of the superfamily have been determined and include Erwinia chrysanthemi pectate lyase C (PelC) (Yoder et al., 1993;Yoder and Jurnak, 1995), E. chrysanthemi pectate lyase E (PelE) (Lietzke et al., 1994), Bacillus subtilis pectate lyase ( B. subtilis Pel) (Pickersgill et al., 1994), Aspergillus niger pectin lyase A (PLA) (Mayans et al., 1997), and A. niger pectin lyase B (PLB) (Vitali et al., 1998). All share a similar but an unusual structural motif, termed the parallel ␤ helix, in which the ␤ strands are folded into a large, right-handed coil. The enzyme structures differ in the size and conformation of the loops that protrude from the parallel ␤ helix core. As deduced from sequence similarity and site-directed mutagenesis studies, the protruding loops on one side of the parallel ␤ helix form the pectolytic active site (Kita et al., 1996). The structural differences of the loops are believed to be related to subtle differences in the enzymatic and maceration properties of the proteins.Pectate lyases catalyze the cleavage of pectate, the deesterified product of pectin, which is the major component that maintains the structural integrity of cell walls in higher plants The Plant Cell (Carpita and Gibeaut, 1993). The pectate backbone is composed of blocks of polygalacturonic acid (PGA), which is a helical homopolymer of D -galacturonic acid (Gal p A) units linked by ␣ -(1 → 4) glycosidic bonds. The blocks of PGA are separated by stretches in which (1 → 2)-␣ -L -rhamnose residues alternate with Gal p A (McNaught, 1997). Blocks of PGA may contain as many as 200 Gal p A units and span 100 nm (Thibault et al., 1993). Cations are necessary to neutralize PGA in solution and, as a consequence, influence its struct...

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Studies of the length of homogalacturonic regions in pectins by acid hydrolysis

Cited by 260 publications

References 25 publications

An Arabidopsis Cell Wall Proteoglycan Consists of Pectin and Arabinoxylan Covalently Linked to an Arabinogalactan Protein

An Arabidopsis Cell Wall Proteoglycan Consists of Pectin and Arabinoxylan Covalently Linked to an Arabinogalactan Protein

Isolation and characterization of acetylated LM-pectins extracted from okra pods

Structure of a Plant Cell Wall Fragment Complexed to Pectate Lyase C

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