Acetylated forms of polysaccharides | Properties and occurrence |
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Rhamnogalacturonan I | Rhamnogalacturonan I, a group of structurally complex pectic polysaccharides. With a repeating backbone composed of diglycosyl [→ 2)-α-l-Rhap-(1 → 4)-α-d-GalpA-(1 →], branched at O-4/O-3 positions by four different side chain types: (1 → 5)-α-l-arabinan, (1 → 4)-β-d-galactan, arabinogalactan-I, and sometimes with arabinogalactan-II (Pawar et al. 2013; Yapo 2011). It is present in primary cell walls of soft and hardwoods (Pawar et al. 2013) |
Rhamnogalacturonan II | Rhamnogalacturonan II is a low-molecular weight pectic polysaccharide with 5–10 kDa released upon treatment with endo-α-1,4-polygalacturonases. Structurally, rhamnogalacturonan II is a homogalacturonan backbone containing at least 7–9 residues containing five oligosaccharide side chains such as A–E [as described in Pérez et al. (2003)]. Naturally, rhamnogalacturonan II was found to occur in primary cell walls of soft and hard wood, also in cell walls of growing plant cell walls (Pérez et al. 2003) |
Homogalacturonan | Homogalacturonan is one of the major constituents of the pectic polysaccharides. Structurally, it contains long chains of d-galacturonic acid units linked through α-(1 → 4) bonds, which are methyl or acetyl esterified at C-6 position with acetyl/methyl group on O-2 or O-3 positions. It is synthesized from the nucleotide sugars in the Golgi apparatus and are then transported to cell wall in fully methylesterified forms (Sénéchal et al. 2014) |