department of biotechnology

Lectins and glycobiology

Glycobiology is a field of molecular biology concerned with carbohydrates and a diverse group of proteins called lectins, which bind various carbohydrates specifically. Lectins are present in all organisms, which suggests their role in basic biological functions, such as organism development, defence, immune response and many others. Their biological activity is mediated through binding to glycosylated receptors and they are thus involved in various cellular processes, including cell adhesion, migration, differentiation, apoptosis and proliferation. Thus, they possess immunomodulatory properties and have potential roles in cancer.

Our group has isolated several lectins with different sugar-binding specificities from the mushroom clouded agaric (Clitocybe nebularis) using carbohydrate affinity chromatography with immobilized glucose, galactose, sucrose or lactose. Their biological activities, such as haemagglutination, haemolysis, effects on lytic enzymes, action against pests, and effects on human immune and cancer cells are being studied and related to their biochemical properties determined by proteomics methods, including electrophoresis, mass spectrometry, circular dichroism and amino acid sequencing. A more detailed study has been conducted on the N,N-diacetyllactosediamine-specific lectin designated C. nebularis lectin (CNL), which shows inhibitory action on leukemic T cell lines. This lectin was cloned and expressed in Escherichia coli, and its carbohydrate-binding specificity analysed, using glycan microarrays. Its crystal structure has also been determined.

Current research fields on the lectins include:

Immunomodulatory and anticancer properties

The proliferative and adhesive effects of the lectins from C. nebularis on various human immune and cancer cells are being determined.

Pesticidal action

The activity of the lectins against different insects, slugs, nematodes, moulds, and bacteria are being studied for their potential as biological pesticides.

 Identification of target receptors

Further studies are in progress to identify target receptors through which the lectins mediate their activity, and thus to determine the mechanisms of their action.
CNL 3d a
CNL 3D b
T limfo

Selected publications:

  •  Pohleven J, Renko M, Magister Š, Smith DF, Künzler M, Štrukelj B, Turk D, Kos J, Sabotič J. Bivalent carbohydrate binding is required for biological activity of CNL, the LacdiNAc (GalNAc[beta]1-4GlcNAc)-specific lectin from basidiomycete Clitocybe nebularis. J Biol Chem (2012) 287 (13): 10602-10612.
  • Pohleven J, Brzin J, Vrabec L, Leonardi A, Čokl A, Štrukelj B, Kos J, Sabotič J. Basidiomycete Clitocybe nebularis is rich in lectins with insecticidal activities. Appl microbiol biotechnol (2011) 91 (4): 1141-1148.
  • Pohleven J, Obermajer  N, Sabotič J, Anžlovar S, Sepčić K, Kos J, Kralj B, Štrukelj B, Brzin J. Purification, characterization and cloning of a ricin B-like lectin from mushroom Clitocybe nebularis with antiproliferative activity against human leukemic T cells. Biochim biophys acta 2009; 1790 (3): 173-181.
Affinity chromatography

Open access book Affinity Chromatography  (Intech, 2012) with our chapter "Affinity Chromatography of Lectins ", that reviews the carbohydrate affinity chromatography methods for purification of lectins.
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