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Lectins
Lectins are carbohydrate-binding proteins that are highly specific for sugar groups that are part of other molecules, so cause agglutination of particular cells or precipitation of glycoconjugates and polysaccharides. Lectins have a role in recognition at the cellular and molecular level and play numerous roles in biological recognition phenomena involving cells, carbohydrates, and proteins. Lectins also mediate attachment and binding of bacteria, viruses, and fungi to their intended targets. Lectins are found in many foods. Some foods, such as beans and grains, need to be cooked, fermented or sprouted to reduce lectin content. Some lectins are beneficial, such as CLEC11A, which promotes bone growth, while others may be powerful toxins such as ricin. Lectins may be disabled by specific mono- and oligosaccharides, which bind to ingested lectins from grains, legumes, nightshade plants, and dairy; binding can prevent their attachment to the carbohydrates within the cell mem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Concanavalin A
Concanavalin A (ConA) is a lectin (carbohydrate-binding protein) originally extracted from the jack-bean (''Canavalia ensiformis''). It is a member of the legume lectin family. It binds specifically to certain structures found in various sugars, glycoproteins, and glycolipids, mainly internal and nonreducing terminal α-D-Mannose, mannosyl and α-D-glucosyl groups. Its physiological function in plants, however, is still unknown. ConA is a plant mitogen, and is known for its ability to stimulate mouse T-cell subsets giving rise to four functionally distinct T cell populations, including precursors to regulatory T cells; a subset of human suppressor T-cells is also sensitive to ConA. ConA was the first lectin to be available on a commercial basis, and is widely used in biology and biochemistry to characterize glycoproteins and other sugar-containing entities on the surface of various cells. It is also used to purify glycosylated macromolecules in lectin affinity chromatography, as w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metabolic reactions, DNA replication, Cell signaling, responding to stimuli, providing Cytoskeleton, structure to cells and Fibrous protein, organisms, and Intracellular transport, transporting molecules from one location to another. Proteins differ from one another primarily in their sequence of amino acids, which is dictated by the Nucleic acid sequence, nucleotide sequence of their genes, and which usually results in protein folding into a specific Protein structure, 3D structure that determines its activity. A linear chain of amino acid residues is called a polypeptide. A protein contains at least one long polypeptide. Short polypeptides, containing less than 20–30 residues, are rarely considered to be proteins and are commonly called pep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ricin
Ricin ( ) is a lectin (a carbohydrate-binding protein) and a highly potent toxin produced in the seeds of the castor oil plant, ''Ricinus communis''. The median lethal dose (LD50) of ricin for mice is around 22 micrograms per kilogram of body weight via intraperitoneal injection. Oral exposure to ricin is far less toxic. An estimated lethal oral dose in humans is approximately one milligram per kilogram of body weight. Ricin is a toxalbumin and was first described by Peter Hermann Stillmark, the founder of lectinology. Ricin is chemically similar to Robin (toxin), robin. Biochemistry Ricin is classified as a type 2 ribosome-inactivating protein (RIP). Whereas type 1 RIPs are composed of a single protein chain that possesses catalytic activity, type 2 RIPs, also known as holotoxins, are composed of two different protein chains that form a heterodimeric complex. Type 2 RIPs consist of an A chain that is functionally equivalent to a type 1 RIP, covalently connected by a single ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peanut Agglutinin
Peanut agglutinin (PNA) is plant lectin protein derived from the fruits of '' Arachis hypogaea''. Peanut agglutinin may also be referred to as ''Arachis hypogaea'' lectin. Lectins recognise and bind particular sugar sequences in carbohydrates; peanut agglutinin binds the carbohydrate sequence Gal-β(1-3)- GalNAc. The name "peanut agglutinin" originates from its ability to stick together ( agglutinate) cells, such as neuraminidase-treated erythrocytes, which have glycoproteins or glycolipids on their surface which include the Gal-β(1-3)-GalNAc carbohydrate sequence. Structure The protein is 273 amino acids in length with the first 23 residues acting as a signal peptide which is subsequently cleaved. It has a Uniprot accession oP02872 There are over 20 structures of this protein in the PDB which reveal and all beta-sheet protein with a tetrameric quaternary structure. It is a member of the Lectin_legB PFAM family.Available Structures of peanut agglutinin Uses in cell biology an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hemagglutinin Lateral
The term hemagglutinin (alternatively spelt ''haemagglutinin'', from the Greek , 'blood' + Latin , 'glue') refers to any protein that can cause red blood cells (erythrocytes) to clump together ("Agglutination (biology), agglutinate") ''in vitro''. They do this by binding to the sugar residues on a red blood cell; when a single hemagglutinin molecule binds sugars from multiple red blood cells, it "glues" these cells together. As a result, they are carbohydrate-binding proteins (lectins). The ability to bind red blood cell sugars have independently appeared several times, and as a result hemaglutinins do not all bind using the same mechanism. The ability to bind red blood sugars is also not necessarily related to the ''in vivo'' function of the protein. The term ''hemagglutinin'' is most commonly applied to plant and viral lectins. Natural proteins that clump together red blood cells were known since the turn of the 19th century. Virologist George Hirst (virologist), George K. Hirst ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vicia Villosa
''Vicia'' is a genus of over 240 species of flowering plants that are part of the legume family (Fabaceae), and which are commonly known as vetches. Member species are native to Europe, North America, South America, Asia and Africa. Some other genera of their subfamily Faboideae also have names containing "vetch", for example the vetchlings ('' Lathyrus'') or the milk-vetches ('' Astragalus''). The lentils are included in genus ''Vicia'', and were formerly classified in genus ''Lens''. The broad bean (''Vicia faba'') is sometimes separated in a monotypic genus ''Faba''; although not often used today, it is of historical importance in plant taxonomy as the namesake of the order Fabales, the Fabaceae and the Faboideae. The tribe Vicieae in which the vetches are placed is named after the genus' current name. The true peas ('' Pisum'') are among the closest living relatives of vetches. Use by humans Bitter vetch ('' V. ervilia'') was one of the first domesticated crops. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Artocarpus Integrifolius
''Artocarpus integer'', commonly known as chempedak or cempedak, is a species of tree in the family Moraceae, in the same genus as breadfruit and jackfruit. It is native to Southeast Asia. Cempedak is an important crop in Malaysia and is also popularly cultivated in southern Thailand and parts of Indonesia, and has the potential to be utilized in other areas. It is currently limited in range to Southeast Asia, with some trees in Australia and Hawaii. Description Cempedak trees are large, evergreen trees. They can grow to a height of 20 m, although most reach only a dozen meters. The trees are monoecious, with male and female flowers growing on the same tree. There are many varieties, although few are named. The vigorously growing tree can bear heavy crops of fruit once or twice a year. Fruit The syncarp may be cylindrical to spherical in shape, and ranges from 10 to 15 cm across and 20 to 35 cm in length.. 1997. ''Artocarpus integer'' (Thunb.) Merr. dalam Verheij, E.W. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jacalin
Jacalin is a plant-based lectin, but not a legume lectin, found in jackfruit. It has been studied for capturing O-glycoproteins such as mucins and IgA1, for potential applications in human immunology. Jacalin belongs to a family of galactose-binding lectins containing the Jacalin-like lectin domain and it has a tetrameric two-chain structure with a weight of 66 kDa Jacalin is preferably used in applications to isolate IgA from human serum, isolating human plasma glycoproteins and for applications in histochemistry. The lectin is blood group non-specific after neuraminidase treatment and agglutinates human erythrocytes at a concentration of ≥ 7,8 μg/mL. A post-translational proteolytic modification of Jacalin gives the lectin a novel carbohydrate-binding site involving the N-terminus of the a-chain. The relative affinities of the lectin for galactose derivatives, as well as the structural basis of its T-antigen specificity, are explained by its protein structure See also ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
