Concanavalin A Explained

Concanavalin A
Symbol:ConA
Organism:Canavalia ensiformis (jackbean)
Pdb:3CNA
Uniprot:P81461

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-mannosyl and α-D-glucosyl groups.[1] [2] 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;[3] a subset of human suppressor T-cells is also sensitive to ConA.[3] 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.[4] It is also used to purify glycosylated macromolecules in lectin affinity chromatography,[5] as well as to study immune regulation by various immune cells.[3]

Structure and properties

Like most lectins, ConA is a homotetramer: each sub-unit (26.5kDa, 235 amino-acids, heavily glycated) binds a metallic atom (usually Mn2+ and a Ca2+). It has the D2 symmetry. Its tertiary structure has been elucidated,[6] as have the molecular basis of its interactions with metals as well as its affinity for the sugars mannose and glucose[7] are well known.

ConA binds specifically α-D-mannosyl and α-D-glucosyl residues (two hexoses differing only in the alcohol on carbon 2) in terminal position of ramified structures from B-Glycans (rich in α-mannose, or hybrid and bi-antennary glycan complexes). It has 4 binding sites, corresponding to the 4 sub-units. The molecular weight is 104–112 kDa and the isoelectric point (pI) is in the range of 4.5–5.5.

ConA can also initiate cell division (mitogenesis), primarily acting on T-lymphocytes, by stimulating their energy metabolism within seconds of exposure.[8]

Maturation process

ConA and its variants (found in closely related plants) are the only proteins known to undergo a post-translational sequence arrangement known as Circular permutation in proteins whereby the N-terminal half of the conA precursor is swapped to become the C-terminal half in the mature form; all other known circular permutations occur at the genetic level.[9] [10] ConA circular permutation is carried out by jack bean asparaginyl endopeptidase,[11] a versatile enzyme capable of cleaving and ligating peptide substrates at a single active site.[12] To convert conA to the mature form, jack bean asparaginyl endopeptidase cleaves the precursor of conA in the middle and ligates the two original termini.

Biological activity

Concanavalin A interacts with diverse receptors containing mannose carbohydrates, notably rhodopsin, blood group markers, insulin receptors,[13] the immunoglobulins and the carcino-embryonary antigen (CEA). It also interacts with lipoproteins.[14]

ConA strongly agglutinates erythrocytes irrespective of blood-group, and various cancerous cells.[15] [16] [17] It was demonstrated that transformed cells and trypsin-treated normal cells do not agglutinate at 4 °C, thereby suggesting that there is a temperature-sensitive step involved in ConA-mediated agglutination.[18] [19]

ConA-mediated agglutination of other cell types has been reported, including muscle cells,[20] B-lymphocytes (through surface immunoglobulins),[21] fibroblasts,[22] rat thymocytes,[23] human fetal (but not adult) intestinal epithelial cells,[24] and adipocytes.[25]

ConA is a lymphocyte mitogen. Similar to phytohemagglutinin (PHA), it is a selective T cell mitogen relative to its effects on B cells. PHA and ConA bind and cross-link components of the T cell receptor, and their ability to activate T cells is dependent on expression of the T cell receptor.[26] [27]

ConA interacts with the surface mannose residues of many microbes, including the bacteria E. coli,[28] and Bacillus subtilis[29] and the protist Dictyostelium discoideum.[30]

It has also been shown as a stimulator of several matrix metalloproteinases (MMPs).[31]

ConA has proven useful in applications requiring solid-phase immobilization of glycoenzymes, especially those that have proved difficult to immobilize by traditional covalent coupling. Using ConA-couple matrices, such enzymes may be immobilized in high quantities without a concurrent loss of activity or stability. Such noncovalent ConA-glycoenzyme couplings may be relatively easily reversed by competition with sugars or at acidic pH. If necessary for certain applications, these couplings can be converted to covalent bindings by chemical manipulation.[32]

A report from Taiwan (2009) demonstrated potent therapeutic effect of ConA against experimental hepatoma (liver cancer); in the study by Lei and Chang,[33] ConA was found to be sequestered more by hepatic tumor cells, in preference to surrounding normal hepatocytes. Internalization of ConA occurs preferentially to the mitochondria after binding to cell membrane glycoproteins, which triggers an autophagic cell death. ConA was found to partially inhibit tumor nodule growth independent of its lymphocyte activation; the eradication of the tumor in the murine in-situ hepatoma model in this study was additionally attributed to the mitogenic/lymphoproliferative action of ConA that may have activated a CD8+ T-cell-mediated, as well as NK- and NK-T cell-mediated, immune response in the liver.

ConA intravitreal injection can be used in the modeling of proliferative vitreoretinopathy in rats.[34] [35]

External links

Notes and References

  1. Book: Irwin J. . Goldstein . Ronald D. . Poretz . Irvin E. . Liener . Nathan . Sharon . Irwin J. . Goldstein . The Lectins Properties, Functions and Applications in Biology and Medicine . Elsevier . 2012 . Isolation, physicochemical characterization, and carbohydrate-binding specificity of lectins . https://books.google.com/books?id=uiwd4XqOLbMC&pg=PA33 . 33–247 . 978-0-323-14444-5 .
  2. Sumner JB, Gralën N, Eriksson-Quensel IB . The Molecular Weights of Urease, Canavalin, Concanavalin a and Concanavalin B . Science . 87 . 2261 . 395–396 . April 1938 . 17746464 . 10.1126/science.87.2261.395 . 1938Sci....87..395S .
  3. Dwyer JM, Johnson C . The use of concanavalin A to study the immunoregulation of human T cells . Clinical and Experimental Immunology . 46 . 2 . 237–249 . November 1981 . 6461456 . 1536405 . John Dwyer (medicine) .
  4. Schiefer HG, Krauss H, Brunner H, Gerhardt U . Ultrastructural visualization of surface carbohydrate structures on mycoplasma membranes by concanavalin A . Journal of Bacteriology . 124 . 3 . 1598–1600 . December 1975 . 1104592 . 236075 . 10.1128/JB.124.3.1598-1600.1975 .
  5. http://www.gelifesciences.com/aptrix/upp01077.nsf/Content/protein_purification~affinity~immobilized_lectin GE Healthcare Life Sciences, Immobilized lectin
  6. Min W, Dunn AJ, Jones DH . Non-glycosylated recombinant pro-concanavalin A is active without polypeptide cleavage . The EMBO Journal . 11 . 4 . 1303–1307 . April 1992 . 1563347 . 556578 . 10.1002/j.1460-2075.1992.tb05174.x .
  7. Loris R, Hamelryck T, Bouckaert J, Wyns L . Legume lectin structure . Biochimica et Biophysica Acta (BBA) - Protein Structure and Molecular Enzymology . 1383 . 1 . 9–36 . March 1998 . 9546043 . 10.1016/S0167-4838(97)00182-9 .
  8. Krauss S, Buttgereit F, Brand MD . Effects of the mitogen concanavalin A on pathways of thymocyte energy metabolism . Biochimica et Biophysica Acta (BBA) - Bioenergetics . 1412 . 2 . 129–138 . June 1999 . 10393256 . 10.1016/S0005-2728(99)00058-4 . free .
  9. Carrington DM, Auffret A, Hanke DE . Polypeptide ligation occurs during post-translational modification of concanavalin A . Nature . 1985 . 313 . 5997 . 64–67 . 3965973 . 10.1038/313064a0 . 1985Natur.313...64C . 4359482 .
  10. Hendrix RW . Protein carpentry . Current Biology . 1 . 2 . 71–73 . April 1991 . 15336168 . 10.1016/0960-9822(91)90280-a . 45963307 .
  11. Nonis SG, Haywood J, Schmidberger JW, Mackie ER, Soares da Costa TP, Bond CS, Mylne JS . Structural and biochemical analyses of concanavalin A circular permutation by jack bean asparaginyl endopeptidase . The Plant Cell . 33 . 8 . 2794–2811 . August 2021 . 34235541 . 10.1093/plcell/koab130 . 8408470 .
  12. Nonis SG, Haywood J, Mylne JS . Plant asparaginyl endopeptidases and their structural determinants of function . Biochemical Society Transactions . 49 . 2 . 965–976 . April 2021 . 33666219 . 10.1042/BST20200908 . 8106488 .
  13. Cuatrecasas P, Tell GP . Insulin-like activity of concanavalin A and wheat germ agglutinin--direct interactions with insulin receptors . Proceedings of the National Academy of Sciences of the United States of America . 70 . 2 . 485–489 . February 1973 . 4510292 . 433288 . 10.1073/pnas.70.2.485 . free . 1973PNAS...70..485C . 62526 .
  14. Harmony JA, Cordes EH . Interaction of human plasma low density lipoprotein with concanavalin A and with ricin . The Journal of Biological Chemistry . 250 . 22 . 8614–8617 . November 1975 . 171260 . 10.1016/S0021-9258(19)40714-X . free .
  15. Betton GR . Agglutination reactions of spontaneous canine tumour cells, induced by concanavalin A, demonstrated by an isotopic assay . International Journal of Cancer . 18 . 5 . 687–696 . November 1976 . 992901 . 10.1002/ijc.2910180518 . 36612952 .
  16. Kakizoe T, Komatsu H, Niijima T, Kawachi T, Sugimura T . Increased agglutinability of bladder cells by concanavalin A after administration of carcinogens . Cancer Research . 40 . 6 . 2006–2009 . June 1980 . 7371036 .
  17. Becker FF, Shurgin A . Concanavalin A agglutination of cells from primary hepatocellular carcinomas and hepatic nodules induced by N-2-fluorenylacetamide . Cancer Research . 35 . 10 . 2879–2883 . October 1975 . 168971 .
  18. Inbar M, Ben-Bassat H, Sachs L . A specific metabolic activity on the surface membrane in malignant cell-transformation . Proceedings of the National Academy of Sciences of the United States of America . 68 . 11 . 2748–2751 . November 1971 . 4330939 . 389516 . 10.1073/pnas.68.11.2748 . free . 1971PNAS...68.2748I . 61219 .
  19. Sela BA, Lis H, Sharon N, Sachs L . Quantitation of N-acetyl-D-galactosamine-like sites on the surface membrane of normal and transformed mammalian cells . Biochimica et Biophysica Acta (BBA) - Biomembranes . 249 . 2 . 564–568 . December 1971 . 4332414 . 10.1016/0005-2736(71)90132-5 .
  20. Gartner TK, Podleski TR . Evidence that a membrane bound lectin mediates fusion of L6 myoblasts . Biochemical and Biophysical Research Communications . 67 . 3 . 972–978 . December 1975 . 1201086 . 10.1016/0006-291X(75)90770-6 .
  21. de Petris S . Concanavalin A receptors, immunoglobulins, and theta antigen of the lymphocyte surface. Interactions with concanavalin A and with Cytoplasmic structures . The Journal of Cell Biology . 65 . 1 . 123–146 . April 1975 . 1092699 . 2111157 . 10.1083/jcb.65.1.123 .
  22. Noonan KD, Burger MM . The relationship of concanavalin A binding to lectin-initiated cell agglutination . The Journal of Cell Biology . 59 . 1 . 134–142 . October 1973 . 4201706 . 2110924 . 10.1083/jcb.59.1.134 .
  23. Capo C, Garrouste F, Benoliel AM, Bongrand P, Ryter A, Bell GI . Concanavalin-A-mediated thymocyte agglutination: a model for a quantitative study of cell adhesion . Journal of Cell Science . 56 . 21–48 . August 1982 . 7166565 . 10.1242/jcs.56.1.21 .
  24. Weiser MM . Concanavalin A agglutination of intestinal cells from the human fetus . Science . 177 . 4048 . 525–526 . August 1972 . 5050484 . 10.1126/science.177.4048.525 . 23661797 . 1972Sci...177..525W .
  25. Cuatrecasas P . Interaction of wheat germ agglutinin and concanavalin A with isolated fat cells . Biochemistry . 12 . 7 . 1312–1323 . March 1973 . 4696755 . 10.1021/bi00731a011 .
  26. Weiss A, Shields R, Newton M, Manger B, Imboden J . Ligand-receptor interactions required for commitment to the activation of the interleukin 2 gene . Journal of Immunology . 138 . 7 . 2169–2176 . April 1987 . 10.4049/jimmunol.138.7.2169 . 3104454 . 35173412 . free .
  27. Kanellopoulos JM, De Petris S, Leca G, Crumpton MJ . The mitogenic lectin from Phaseolus vulgaris does not recognize the T3 antigen of human T lymphocytes . European Journal of Immunology . 15 . 5 . 479–486 . May 1985 . 3873340 . 10.1002/eji.1830150512 . 21414006 .
  28. Ofek I, Mirelman D, Sharon N . Adherence of Escherichia coli to human mucosal cells mediated by mannose receptors . Nature . 265 . 5595 . 623–625 . February 1977 . 323718 . 10.1038/265623a0 . 4223466 . 1977Natur.265..623O .
  29. Doyle RJ, Birdsell DC . Interaction of concanavalin A with the cell wall of Bacillus subtilis . Journal of Bacteriology . 109 . 2 . 652–658 . February 1972 . 4621684 . 285189 . 10.1128/JB.109.2.652-658.1972 .
  30. West CM, McMahon D . Identification of concanavalin A receptors and galactose-binding proteins in purified plasma membranes of Dictyostelium discoideum . The Journal of Cell Biology . 74 . 1 . 264–273 . July 1977 . 559679 . 2109878 . 10.1083/jcb.74.1.264 .
  31. Yu M, Sato H, Seiki M, Thompson EW . Complex regulation of membrane-type matrix metalloproteinase expression and matrix metalloproteinase-2 activation by concanavalin A in MDA-MB-231 human breast cancer cells . Cancer Research . 55 . 15 . 3272–3277 . August 1995 . 7614461 .
  32. Saleemuddin M, Husain Q . Concanavalin A: a useful ligand for glycoenzyme immobilization--a review . Enzyme and Microbial Technology . 13 . 4 . 290–295 . April 1991 . 1367163 . 10.1016/0141-0229(91)90146-2 .
  33. Lei HY, Chang CP . Lectin of Concanavalin A as an anti-hepatoma therapeutic agent . Journal of Biomedical Science . 16 . 10 . January 2009 . 1 . 19272170 . 2644972 . 10.1186/1423-0127-16-10 . free .
  34. Erdiakov AK, Tikhonovich MV, Rzhavina EM, Gavrilova SA . [The characteristics of retina at the development of proliferative vitreoretinopathy in rats after intraocular injection of concanavalin a and dispase] . Rossiĭskii Fiziologicheskiĭ Zhurnal Imeni I.M. Sechenova . 101 . 5 . 572–585 . May 2015 . 26263683 .
  35. Tikhonovich MV, Erdiakov AK, Gavrilova SA . Nonsteroid anti-inflammatory therapy suppresses the development of proliferative vitreoretinopathy more effectively than a steroid one . International Ophthalmology . 38 . 4 . 1365–1378 . August 2018 . 28639085 . 10.1007/s10792-017-0594-3 . 4017540 .

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Concanavalin A".

Except where otherwise indicated, Everything.Explained.Today is © Copyright 2009-2024, A B Cryer, All Rights Reserved. Cookie policy.