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Abstract

Pectin is a major component of primary cell walls of all land plants and encompasses a range of galacturonic acid-rich polysaccharides. Three major pectic polysaccharides (homogalacturonan, rhamnogalacturonan-I and rhamnogalacturonan-II) are thought to occur in all primary cell walls. This review surveys what is known about the structure and function of these pectin domains. The high degree of structural complexity and heterogeneity of the pectic matrix is produced both during biosynthesis in the endomembrane system and as a result of the action of an array of wall-based pectin-modifying enzymes. Recent developments in analytical techniques and in the generation of anti-pectin probes have begun to place the structural complexity of pectin in cell biological and developmental contexts. The in muro de-methyl-esterification of homogalacturonan by pectin methyl esterases is emerging as a key process for the local modulation of matrix properties. Rhamnogalacturonan-I comprises a highly diverse population of spatially and developmentally regulated polymers, whereas rhamnogalacturonan-II appears to be a highly conserved and stable pectic domain. Current knowledge of biosynthetic enzymes, plant and microbial pectinases and the interactions of pectin with other cell wall components and the impact of molecular genetic approaches are reviewed in terms of the functional analysis of pectic polysaccharides in plant growth and development.

Plant Pectin: A Potential Source for Cancer Suppression

“…Pectin molecules are an extremely complex and structurally diverse group of polymers. The fine structures of pectins can be widely heterogeneous between plants, tissues and even within a single cell wall (Willats et al, 2001). The composition of pectin varies in plant species and is dependent on the age and maturity of the plant parts.…”

“…A notable feature of galectin-3 is its implication in neoplastic transformation and cancer progression. A direct relationship has been shown between galectin-3 levels and the stage of progression of some tumors (Inohara and Raz, 1994;Willats et al, 2001). In regards to pectin and MCP, in its native form Citrus Pectin (CP) has limited solubility in water and is unable to interact with galectin-3, but in its modified form MCP is able to form small linear water-soluble fibers.…”

Functional identification of an Arabidopsis pectin biosynthetic homogalacturonan galacturonosyltransferase

“…Numerous studies show that pectins contribute to the physical and biochemical properties of the wall (1) and are required for normal plant growth and development (4). A complete understanding of pectin function requires knowledge of pectin biosynthetic enzymes and their corresponding genes.…”

LASSO modeling of the Arabidopsis thaliana seed/seedling transcriptome: a model case for detection of novel mucilage and pectin metabolism genes

“…38,39 Once released, mucilage is characterized by a denser, relatively insoluble, inner layer and a more soluble outer layer, composed of sparsely branched rhamnogalacturonan I (RGI), a polysaccharide formed by succession of L-rhamnose-D-galacturonic acid dimers with side chains of arabinose, galactose and arabinogalactan residues. 36,37,40 Due to its composition, it can be considered as a model to study pectin biosynthesis. Unlike in other plant tissues, mucilage can be easily extracted from Arabidopsis seeds and Arabidopsis plants can tolerate the absence of mucilage under laboratory conditions.…”