LECTIN

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  1. Lectinity Holding, Inc. - Offer custom synthesis of tailored PAA-glucoconjugate, glycoarrays, glycoparticles, glycosurfaces and adsorbents. Includes applications, publications and links to worldwide distributors, with customer services in Moscow, Russia.
  2. Glycobiology - Provides a unique forum dedicated to research into the structure and function of glyconjugates (including glycoproteins, glycolipids, proteoglycans or free complex saccharides) or on any aspect of proteins that specifically interact with glyconjugates (e.g. lectins, glycotransferases, glycosidases).
  3. Galab Technologies GmbH. - Offers reagents and kits for separation for glycosciences, such as lectins. Also offering process development and quality control for food, hygiene and pharmaceutical and environmental analysis in Geesthacht, Germany.


  4. [ Link Deletion Request ]

    lectin definition lectins in food lectin lock lectin foods lectin free diet mannose binding lectin lectin pathway ultimate lectin defense



    Lectin


    Lateral hemagglutinine

    The lectins are carbohydrate-binding proteins (not to be confused with glycoproteins, which are proteins containing sugar chains or residues) that are highly specific for sugar moieties, particularly, the high specificity of plant lectins for foreign glycoconjugates (e.g. those of fungi, invertebrates and animals).[1] They play a role in the biological recognition phenomena involving cells and proteins.[2][3] It is hypothesized that some hepatitis C viral glycoproteins attach to C-type lectins on the host cell surface (liver cells) for infection.[4] Lectins may be disabled by specific mono- and oligosaccharides, which bind to ingested lectins from grains, legume, nightshade plants and dairy; binding can prevent their attachment to the carbohydrates within the cell membrane.[5]


    Lectin Etymology


    Table of the major lectins [6]
      Lectin Symbol Lectin name Source ligand motif
    Mannose binding lectins
    ConA Concanavalin A Canavalia ensiformis α-D-mannosyl and α-D-glucosyl residues

    branched α-mannosidic structures (high α-mannose type, or hybrid type and biantennary complex type N-Glycans)

    LCH Lentil lectin Lens culinaris Fucosylated core region of bi- and triantennary complex type N-Glycans
    GNA Snowdrop lectin Galanthus nivalis α 1-3 and α 1-6 linked high mannose structures
    Galactose / N-acetylgalactosamine binding lectins
    RCA Ricin, Ricinus communis Agglutinin, RCA120 Ricinus communis Galβ1-4GalNAcβ1-R
    PNA Peanut agglutinin Arachis hypogaea Galβ1-3GalNAcα1-Ser/Thr (T-Antigen)
    AIL Jacalin Artocarpus integrifolia (Sia)Galβ1-3GalNAcα1-Ser/Thr (T-Antigen)
    VVL Hairy vetch lectin Vicia villosa GalNAcα-Ser/Thr (Tn-Antigen)
    N-acetylglucosamine binding lectins
    WGA Wheat Germ Agglutinin, WGA Triticum vulgaris GlcNAcβ1-4GlcNAcβ1-4GlcNAc, Neu5Ac (sialic acid)
    N-acetylneuraminic acid binding lectins
    SNA Elderberry lectin Sambucus nigra Neu5Acα2-6Gal(NAc)-R
    MAL Maackia amurensis leukoagglutinin Maackia amurensis Neu5Ac/Gcα2,3Galβ1,4Glc(NAc)
    MAH Maackia amurensis hemoagglutinin Maackia amurensis Neu5Ac/Gcα2,3Galβ1,3(Neu5Acα2,6)GalNac
    Fucose binding lectins
    UEA Ulex europaeus agglutinin Ulex europaeus Fucα1-2Gal-R
    AAL Aleuria aurantia lectin Aleuria aurantia Fucα1-2Galβ1-4(Fucα1-3/4)Galβ1-4GlcNAc,

    R2-GlcNAcβ1-4(Fucα1-6)GlcNAc-R1

    The name "lectin" is derived from the Latin word legere, meaning, among other things, "to select".(lek'tin)


    Lectin History


    Although they were first discovered more than 100 years ago in plants, lectins are now known to be present throughout nature. It is generally believed that the earliest description of a lectin was given by Peter Hermann Stillmark in his doctoral thesis presented in 1888 to the University of Dorpat. Stillmark isolated ricin, an extremely toxic hemagglutinin, from seeds of the castor plant (Ricinus communis). The first lectin to be purified on a large scale and available on a commercial basis was concanavalin A, which is now the most-used lectin for characterization and purification of sugar-containing molecules and cellular structures. The legume lectins are probably the most well-studied lectins.


    Lectin Biological functions


    Most lectins do not possess enzymatic activity and are not produced naturally by the immune system. Lectins occur ubiquitously in nature. They may bind to a soluble carbohydrate or to a carbohydrate moiety that is a part of a glycoprotein or glycolipid. They typically agglutinate certain animal cells and/or precipitate glycoconjugates.

    An oligosaccharide (shown in grey) bound in the binding site of a plant lectin (Griffonia simplicifolia isolectin IV in complex with the Lewis b blood group determinant). Only a part of the oligosaccharide (central, in grey) is shown for clarity.

    Lectin Functions in animals

    Lectins serve many different biological functions in animals, from the regulation of cell adhesion to glycoprotein synthesis and the control of protein levels in the blood. They may also bind soluble extracellular and intercellular glycoproteins. Some lectins are found on the surface of mammalian liver cells that specifically recognize galactose residues. It is believed that these cell-surface receptors are responsible for the removal of certain glycoproteins from the circulatory system. Another lectin is a receptor that recognizes hydrolytic enzymes containing mannose-6-phosphate, and targets these proteins for delivery to the lysosomes. I-cell disease is one type of defect in this particular system. Lectins are also known to play important roles in the immune system by recognizing carbohydrates that are found exclusively on pathogens, or that are inaccessible on host cells. Examples are the lectin complement activation pathway and mannose-binding lectin.


    Lectin Functions in plants

    Leucoagglutinin, a toxic phytohemagglutinin found in raw Vicia faba

    The function of lectins in plants (legume lectin) is still uncertain. Once thought to be necessary for rhizobia binding, this proposed function was ruled out through lectin-knockout transgene studies.[7]

    The large concentration of lectins in plant seeds decreases with growth, and suggests a role in plant germination and perhaps in the seed's survival itself. The binding of glycoproteins on the surface of parasitic cells is also believed to be a function. Several plant lectins have been found to recognise non-carbohydrate ligands that are primarily hydrophobic in nature, including adenine, auxins, cytokinin, and indole acetic acid, as well as water-soluble porphyrins. It has been suggested that these interactions may be physiologically relevant, since some of these molecules function as phytohormones.[8] are another major family of protein ANCs, which are specific sugar-binding proteins exhibiting reversible carbohydrate-binding activities.

    Lectins are similar to antibodies in their ability to agglutinate red blood cells; however, lectins are not immune system products. The toxicity of lectins has been identified by consumption of food with high lectin content, which can lead to diarrhea, nausea, bloating, vomiting, even death (as from ricin). Many legume seeds have been proven to contain high lectin activity, termed hemagglutinating activity. Soybean is the most important grain legume crop, the seeds of which contain high activity of soybean lectins (soybean agglutinin or SBA). SBA is able to disrupt small intestinal metabolism and damage small intestinal villi via the ability of lectins to bind with brush border surfaces in the distal part of small intestine.[citation needed] Heat processing can reduce the toxicity of lectins, but low temperature or insufficient cooking may not completely eliminate their toxicity, as some plant lectins are resistant to heat. (It is believed that undercooking red kidney beans increases toxicity.) In addition, lectins can result in irritation and over-secretion of mucus in the intestines, causing impaired absorptive capacity of the intestinal wall.[citation needed]


    Lectin Use in science, medicine and technology



    Lectin Use in medicine and medical research

    Purified lectins are important in a clinical setting because they are used for blood typing.[9] Some of the glycolipids and glycoproteins on an individual's red blood cells can be identified by lectins.

    • A lectin from Dolichos[disambiguation needed] biflorus is used to identify cells that belong to the A1 blood group.
    • A lectin from Ulex europaeus is used to identify the H blood group antigen.
    • A lectin from Vicia graminea is used to identify the N blood group antigen.
    • A lectin from Iberis amara is used to identify the M blood group antigen.
    • A lectin from coconut milk is used to identify Theros antigen.
    • A lectin from Dorex is used to identify R antigen.

    In neuroscience, the anterograde labeling method is used to trace the path of efferent axons with PHA-L, a lectin from the kidney bean.[10]

    A lectin (BanLec) from bananas inhibits HIV-1 in vitro.[11] Achylectins, isolated from Tachypleus tridentatus, show specific agglutinating activity against human A-type erythrocytes. Anti-B agglutinins such as anti-BCJ and anti-BLD separated from Charybdis japonica and Lymantria dispar, respectively, are of value both in routine blood grouping and research.[12]


    Lectin Use in studying carbohydrate recognition by proteins

    Lectins from legume plants, such as PHA or concanavalin A, have been widely used as model systems to understand the molecular basis of how proteins recognize carbohydrates, because they are relatively easy to obtain and have a wide variety of sugar specificities. The many crystal structures of legume lectins have led to a detailed insight of the atomic interactions between carbohydrates and proteins.


    Lectin Use as a biochemical tool

    Concanavalin A and other commercially available lectins have been widely used in affinity chromatography for purifying glycoproteins.[13]

    In general, proteins may be characterized with respect to glycoforms and carbohydrate structure by means of affinity chromatography, blotting, affinity electrophoresis and affinity immunoelectrophoreis with lectins as well as in microarrays, as in evanescent-field fluorescence-assisted lectin microarray.[14]


    Lectin Use in biochemical warfare

    One example of the powerful biological attributes of lectins is the biochemical warfare agent ricin. The protein ricin is isolated from seeds of the castor oil plant and comprises two protein domains. Abrin from the jequirity pea is similar:

    • One domain is a lectin that binds cell surface galactosyl residues and enables the protein to enter cells
    • The second domain is an N-glycosidase that cleaves nucleobases from ribosomal RNA, resulting in inhibition of protein synthesis and cell death.

    Lectin Toxicity



    Lectin Digestion and immune distress

    Foods with high concentrations of lectins, such as beans, cereal grains, seeds, nuts, and potatoes, may be harmful if consumed in excess in uncooked or improperly cooked form. Adverse effects may include nutritional deficiencies, and immune (allergic) reactions.[15] Possibly, most effects of lectins are due to gastrointestinal distress through interaction of the lectins with the gut epithelial cells. A recent in vitro study has suggested that the mechanism of lectin damage may occur by interfering with the repair of already-damaged epithelial cells.[16]


    Lectin Lectin and Leptin Resistance

    Lectin may cause leptin resistance, affecting its functions (signal have high levels of leptin and several effects gathering to protect from lipid overload), as indicated by studies on effects of single nucleotide polymorphisms on the function of leptin and the leptin receptor.[17] Such leptin resistance may translate into diseases, notably it could be responsible for obesity in humans who have high levels of leptin.


    Lectin See also



    Lectin References


    1. ^ Els. J. M. Van Damme, Willy J. Peumans, Arpad Pusztai, Susan Bardocz (March 30, 1998). Handbook of Plant Lectins: Properties and Biomedical Applications. John Wiley & Sons. pp. 7–8. ISBN 978-0-471-96445-2. Retrieved 18 April 2013. 
    2. ^ URS Rutishauser and Leo Sachs (May 1, 1975). "Cell-to-Cell Binding Induced by Different Lectins". Journal of Cell Biology (Rockefeller University Press) 65 (2): 247–257. Retrieved 28 April 2013. 
    3. ^ Matthew Brudner, Marshall Karpel, Calli Lear, Li Chen, L. Michael Yantosca, Corinne Scully, Ashish Sarraju, Anna Sokolovska, M. Reza Zariffard, Damon P. Eisen, Bruce A. Mungall, Darrell N. Kotton, Amel Omari, I-Chueh Huang, Michael Farzan, Kazue Takahashi, Lynda Stuart, Gregory L. Stahl, Alan B. Ezekowitz, Gregory T. Spear, Gene G. Olinger, Emmett V. Schmidt, and Ian C. Michelow1 (April 2, 2013). "Lectin-Dependent Enhancement of Ebola Virus Infection via Soluble and Transmembrane C-type Lectin Receptors". In Bradley S. Schneider. PLoS One. 8 (4 specific e code=e60838). doi:10.1371/journal.pone.0060838. PMC 3614905. Retrieved 18 April 2013. 
    4. ^ R. Bartenschlager, S. Sparacio (2007). "Hepatitis C Virus Molecular Clones and Their Replication Capacity in Vivo and in Cell Culture". Virus Research (Elsevier) 127 (2): 195–207. 
    5. ^ The Lectin Story
    6. ^ "Lectin list". Interchim. 2010. Retrieved 2010-05-05. 
    7. ^ http://www.annualreviews.org/doi/full/10.1146/annurev.arplant.59.032607.092839
    8. ^ Komath SS, Kavitha M, Swamy MJ (March 2006). "Beyond carbohydrate binding: new directions in plant lectin research". Org. Biomol. Chem. 4 (6): 973–88. doi:10.1039/b515446d. PMID 16525538. 
    9. ^ The History of Lectins by N.Sharon
    10. ^ Carlson, Neil R. (2007). Physiology of behavior. Boston: Pearson Allyn & Bacon. ISBN 0-205-46724-5. 
    11. ^ http://www.jbc.org/content/285/12/8646.abstract "A Lectin Isolated from Bananas Is a Potent Inhibitor of HIV Replication" 2010
    12. ^ http://www.tandfonline.com/doi/full/10.1080/11250003.2010.492794 Prospect for lectins in arthropods 2010
    13. ^ Immobilized Lectin
    14. ^ Glyco Station, Lec Chip, Glycan profiling technology
    15. ^ British Journal of Nutrition (2000), 83: 207-217 Cambridge University Press
    16. ^ Miyake K, Tanaka T, McNeil PL (2007). "Lectin-Based Food Poisoning: A New Mechanism of Protein Toxicity". In Steinhardt, Richard. PLoS ONE 2 (1): e687. doi:10.1371/journal.pone.0000687. PMC 1933252. PMID 17668065. 
    17. ^ T Jönsson, S Olsson, B Ahrén , T C Bøg-Hansen, A Dole and S Lindeberg (2005). "Agrarian diet and diseases of affluence – Do evolutionary novel dietary lectins cause leptin resistance?". BioMed Central Ltd.. doi:10.1186/1472-6823-5-10. . http://www.biomedcentral.com/1472-6823/5/10.

    Lectin Further reading



    Lectin External links




    Foods High in Lectins Lectins and Blood Type Lectin Lock Side Effects Lectin Supplement Lectins Rheumatoid Arthritis Lectin Lock Lectin Labs Low Lectin Foods

    | Foods High in Lectins | Lectins and Blood Type | Lectin Lock Side Effects | Lectin Supplement | Lectins Rheumatoid Arthritis | Lectin Lock | Lectin Labs | Low Lectin Foods | Lectin | Lectin_pathway | Mannan-binding_lectin | Legume_lectin | C-type_lectin | Banana_lectin | Leguminous_lectin_family | Jacalin-like_lectin_domain | Fungal_fucose-specific_lectin | L-type_lectin_domain | Galactose_binding_lectin_domain | Fungal_fruit_body_lectin_family | Mannan-binding_lectin-associated_serine_protease-2 | Sialic_acid-binding_Ig-like_lectin_12 | Concanavalin_A | Lectin_affinity_chromatography | Ricin | Phytohaemagglutinin | Collectin | Ficolin

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