Rhamnogalacturonan I in Solanum tuberosum tubers contains complex arabinogalactan structures

Øbro, Jens, Orfila, Caroline, Harholt, Jesper and Sheller, Henrik Vibe (2004) Rhamnogalacturonan I in Solanum tuberosum tubers contains complex arabinogalactan structures. Phytochemistry, 65 (10). pp. 1429-1438. ISSN 0031-9422

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Abstract

A rhamnogalacturonan I polysaccharide was isolated from potato (Solanum tuberosum cv. Posmo) tuber cell walls and characterised by enzymatic digestion with an endo-β-1 → 4-galactanase and an endo-α-1 → 5-arabinanase, individually or in combination. The reaction products were separated using size-exclusion chromatography and further analysed for monosaccharide composition and presence of epitopes using the LM5 anti-β-1 → 4-galactan and LM6 anti-α-1 → 5-arabinan monoclonal antibodies. The analyses point to distinct structural features of potato tuber rhamnogalacturonan I, such as the abundance of β-1 → 4-galactan side chains that are poorly substituted with short arabinose-containing side chains, the presence of α-1 → 5-arabinan side chains substituted with β-1 → 4-galactan oligomers (degree of polymerisation >4), and the presence of α-1 → 5-arabinans that resist enzymatic degradation. A synergy between the enzymes was observed towards the degradation of arabinans but not towards the degradation of galactans. The effect of the enzymes on isolated RG I is discussed in relation to documented effects of enzymes heterologously expressed in potato tubers. In addition, a novel and rapid method for the determination of the monosaccharide and uronic acid composition of cell wall polysaccharides using high-performance anion exchange chromatography with pulsed amperometric detection is described.

A rhamnogalacturonan I polysaccharide from potato tuber cell walls and isolated and characterised by enzymatic digestion with different pectinases. In addition, a novel and rapid method for the determination of common cell wall monosaccharides using high-performance anion exchange chromatography with pulsed amperometric detection is described.

Item Type:	Article
Additional Information:	Supervisor to J. Øbro (PGT student). Orfila designed the project and wrote the manuscript. This was the first paper to describe the structure of potato pectic polysaccharides which is of particular significance as potatoes are one of the main sources of dietary fibre in diets worldwide.
Uncontrolled Keywords:	Pectin, Polysaccharides, Potatoes
Subjects:	C200 Botany
Department:	Faculties > Health and Life Sciences > Applied Sciences
Depositing User:	EPrint Services
Date Deposited:	23 Dec 2008 13:02
Last Modified:	12 Oct 2019 17:30
URI:	http://nrl.northumbria.ac.uk/id/eprint/1886

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