lectinscarbohydratebinding

Lectins are a class of proteins that bind specific carbohydrate structures without catalytic activity. They occur in plants, animals, and microorganisms and are often involved in recognition events at the cellular and molecular levels. Lectins can influence cell adhesion, signaling, and immune interactions by binding to glycoconjugates on cell surfaces or extracellular matrices.

Carbohydrate recognition is mediated by carbohydrate-binding domains that confer specificity to particular sugars, such as galactose, mannose, fucose, or N-acetylglucosamine. Some lectins, notably C-type lectins, require calcium ions for binding, while others depend on different metal ions or operate in a calcium-independent manner. Lectins are frequently multivalent, possessing multiple binding sites that enable crosslinking of glycoconjugates and higher overall affinity through avidity.

Biological roles are diverse. In plants, lectins can contribute to defense against herbivores and pathogens. In animals, they participate in cell-cell adhesion, immune recognition, and pathogen detection. In laboratory settings, lectins are widely used as reagents to detect or purify specific glycans and to study glycosylation patterns.

Health considerations during nutrition include the fact that many plant lectins are resistant to digestion and may interact with the intestinal lining. However, culinary processing such as soaking and heating reduces lectin activity, and raw consumption of some lectins can be harmful. Research continues into potential beneficial effects, including immune modulation and anti-cancer properties, as well as their use as tools in glycomics and biotechnology.

See also glycoprotein, glycan, lectin-based affinity chromatography, and lectin microarrays.