Anti-frost protein

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The anti-frost protein from Choristoneura fumiferana responsible for heat hysteresis
Anti-frost protein from Tenebrio molitor
RiAFP (H4) from Rhagium inquisitor

Antifreeze proteins (AFP), also Eisstrukturierende proteins ( English ice-structuring protein , ISP), antifreeze proteins or thermal hysteresis proteins (THP) are a class of proteins produced by certain vertebrates , plants , fungi and bacteria are made to in to survive in an environment with temperatures below the freezing point of water.

Mode of action

Anti-frost proteins bind to ice crystals and prevent their growth and recrystallization , which would lead to the death of the living being. The proteins can also use cell membranes of mammals interact, in order to preserve them from frost damage.

In contrast to the commercially available antifreeze agents, the antifreeze proteins do not lower the freezing point proportionally to their concentration , but have a non- colligative effect . AFPs lower the freezing point and reduce the formation of ice crystals by binding in a non-colligative manner to the surface of the ice crystals being formed. This allows them to be effective at concentrations that are more than 300 to 500 times lower than common dissolved substances in antifreeze. These concentrations also have no influence on the osmotic pressure . The unusual properties of the anti-frost proteins are due to their attachment to the surface of ice crystals.

Living organisms that contain anti-frost proteins can be divided into frost-avoiding and frost-tolerant species. The frost-avoiding species are able to completely protect their body fluids against freezing. Typically, however, the protection against freezing is removed at extremely low temperatures, which leads to rapid growth of the ice crystals and subsequent death of the living being. The frost-tolerant species are able to survive the freezing of body fluids. Some of these types are associated with the anti-frost proteins, which are effective as cold protection agents and reduce the harmful effects of frost, but do not completely eliminate it. The exact mode of action is still unknown. However, the presence of anti-frost proteins can prevent recrystallization , stabilize cell membranes and thus minimize frost damage . In fish, the anti-frost proteins are largely made up of the amino acid L - alanine and interspersed with L - threonine . In beetles, anti-frost proteins often contain threonine, e.g. B. RiAFP .

development

Sea ravens make anti-frost proteins

The remarkable diversification and distribution of the anti-frost proteins suggests that the different types emerged more recently, in response to the icing of the seas about one to two million years in the northern hemisphere and ten to thirty million years ago in the Antarctica . The different development of similar adaptation processes is called "convergent evolution". There are two reasons why many types of anti-freeze proteins can perform the same function although they are structured differently:

  1. Although ice is made up of oxygen and hydrogen throughout , it has many different surface features that lend itself to bonding; Different types of anti-frost proteins can thus attach to different types of surfaces.
  2. Although the five known types of anti-freeze proteins differ in their primary structure , they have similar three-dimensional or tertiary structures when they unfold into an active protein.

history

In the 1950s, Norwegian-born scientist Per Fredrik Scholander investigated why Arctic fish can survive in water that is below the freezing point of their own blood. His experiments led him to believe that there must be an antifreeze in her blood. In the late 1960s, the zoologist Arthur DeVries was able to isolate the anti-frost protein by examining arctic fish. At the time they were called "Glycoproteins as Biological Antifreeze Agents" and then referred to as antifreeze glycoproteins to differentiate them from the newly discovered biological antifreeze proteins that were not glycoproteins. DeVries and Robert Feeney were then able to characterize the chemical and physical properties of the anti-frost proteins.

In 1992 Griffith published a paper on anti-frost proteins in winter wheat leaves . Around the same time documented Urrutia, Duman and Knight the thermal hysteresis protein (thermal hysteresis) in angiosperms . In 1993, anti-frost proteins were detected in fungi and bacteria.

Discussion on the name

More recently, attempts have been made to give anti-frost proteins the new name "Ice Structuring Proteins" in order to better distinguish them from synthetic anti-freeze agents and their negative image (e.g. ethylene glycol ). The two things are completely different classes of substance and have only a very distant similarity in their effect.

literature

Individual evidence

  1. ↑ SP Graether, MJ Kuiper, SM Gagné, VK Walker, Z. Jia, BD Sykes, PL Davies: beta-helix structure and ice-binding properties of a hyperactive antifreeze protein from an insect. In: Nature . Volume 406, Number 6793, July 2000, pp. 325-328. doi : 10.1038 / 35018610 . PMID 10917537 .
  2. ↑ a b G. L. Fletcher, CL Hew, PL Davies: Antifreeze proteins of teleost fishes. In: Annual Review of Physiology . Volume 63, 2001, pp. 359-390. doi : 10.1146 / annurev.physiol.63.1.359 . PMID 11181960 .
  3. ^ E. Kristiansen, KE Zachariassen: The mechanism by which fish antifreeze proteins cause thermal hysteresis. In: Cryobiology . Volume 51, Number 3, December 2005, pp. 262-280. doi : 10.1016 / j.cryobiol.2005.07.007 . PMID 16140290 .
  4. ↑ H. Kondo, Y. Hanada, H. Sugimoto, T. Hoshino, CP Garnham, PL Davies, S. Tsuda: Ice-binding site of snow mold fungus antifreeze protein deviates from structural regularity and high conservation. In: Proceedings of the National Academy of Sciences . Volume 109, Number 24, June 2012, pp. 9360-9365. doi : 10.1073 / pnas.1121607109 . PMID 22645341 . PMC 3386094 (free full text).
  5. ↑ JG Duman: Antifreeze and ice nucleator proteins in terrestrial arthropods. In: Annual Review of Physiology . Volume 63, 2001, pp. 327-357. doi : 10.1146 / annurev.physiol.63.1.327 . PMID 11181959 .
  6. ↑ KC Chou: Energy-optimized structure of antifreeze protein and its binding mechanism. In: Journal of Molecular Biology . Volume 223, Number 2, January 1992, pp. 509-517. PMID 1738160 .
  7. ^ GC Barrett: Chemistry and Biochemistry of the Amino Acids , Chapman and Hall, London, New York, 1985, p. 11, ISBN 0-412-23410-6 .
  8. ↑ L. Chen, AL DeVries, CH Cheng: Convergent evolution of antifreeze glycoproteins in Antarctic notothenioid fish and Arctic cod. In: Proceedings of the National Academy of Sciences . Volume 94, Number 8, April 1997, pp. 3817-3822. PMID 9108061 . PMC 20524 (free full text).
  9. ^ PF Scholander, L. van Dam, JW Kanwisher, HT Hammel, MS Gordon: Supercooling and osmoregulation in arctic fish . In: Journal of Cellular and Comparative Physiology . tape 49 , no. 1 , February 1957, p. 5-24 , doi : 10.1002 / jcp.1030490103 .

    "When arctic fishes swim about in ice water at -1.7 ° to - 1.8 °, why don't they freeze? Do they have twice as high an oscmotic concentration as ordinary fishes, or what is the story? "

  10. ^ AL DeVries, DE Wohlschlag: Freezing resistance in some Antarctic fishes. In: Science . Volume 163, Number 3871, March 1969, pp. 1073-1075. PMID 5764871 .
  11. ↑ AL DeVries, SK Komatsu, RE Feeney: Chemical and physical properties of freezing point-depressing glycoproteins from Antarctic fishes. In: The Journal of Biological Chemistry . Volume 245, Number 11, June 1970, pp. 2901-2908. PMID 5488456 .
  12. ↑ John G. Duman, T. Mark Olsen: Thermal Hysteresis Protein Activity in Bacteria, Fungi, and Phylogenetically Diverse Plants. In: Cryobiology. 30, 1993, pp. 322-328, doi : 10.1006 / cryo.1993.1031 .
  13. ^ CJ Clarke, SL Buckley, N. Lindner: Ice structuring proteins - a new name for antifreeze proteins. In: CryoLetters . Volume 23, Number 2, 2002 Mar-Apr, pp. 89-92. PMID 12050776 .