Amavadin

Amavadin
Ball-and-stick model of the amavadin dianion
Ball-and-stick model of the amavadin dianion
Names
IUPAC name
bis[N-[(1S)-1-(carboxy-κO)ethyl]-N-(hydroxy-κO)-L-alaninato(2-)-.κN,κO]-vanadium
Identifiers
3D model (JSmol)
ChemSpider
UNII
  • InChI=1S/2C6H10NO5.V/c2*1-3(5(8)9)7(12)4(2)6(10)11;/h2*3-4H,1-2H3,(H,8,9)(H,10,11);/q2*-1;+4/p-4
    Key: JFEAKSQUSDDXGF-UHFFFAOYSA-J
  • CC(C(=O)[O-])N(C(C)C(=O)[O-])[O-].CC(C(=O)[O-])N(C(C)C(=O)[O-])[O-].[V+4]
Properties
[V{NO[CH(CH3)CO2]2}2]2−
Molar mass 398.94 g/mol
Appearance Light blue in solution
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Amavadin is a vanadium-containing coordination complex that occurs naturally. It is found found in three species of poisonous Amanita mushrooms: A. muscaria, A. regalis, and A. velatipes.

History and structure

The ligand found in amavadin was first synthesized in 1954. Amavadin was first isolated and identified in 1972 by Kneifel and Bayer. In 1993, it was discovered by X-ray crystallography that amavadin is not a vanadyl ion complex. Instead, it is an octacoordinated vanadium(IV) complex. This vanadium center is bonded to two tetradentate ligands derived from N-hydroxyimino-2,2'-dipropionic acid, H3(HIDPA), ligands. The ligands coordinate through the nitrogen and the three oxygen centers.

The anionic complex is blue. It is an eight-coordinate vanadium complex. A Ca2+ cation is often used to crystallize amavadin to obtain a good quality X-ray diffraction. Oxidized amavadin can be isolated as its PPh4+ salt. The oxidized form contains vanadium(V), which has been studied by NMR spectroscopy.

The ligand precursor found in amavadin (left), the ligand (center) and H3(HIDA) (right).

Amavadin contains vanadium(IV). Initially, amavadin was thought to have a vanadyl, VO2+, center.

Amavadin is a C2-symmetric anion with a 3− charge. The twofold axis bisects the vanadium atom perpendicular to the two NO ligands. The anion features five chiral centers, one at vanadium and the four carbon atoms having S stereochemistry. There are two possible diastereomers for the ligands, (S,S)-(S,S)-Δ and (S,S)-(S,S)-Λ.

Preparation

The formation of amavadin begins with the binding of two of the ligands.

2 HON(CH(CH3)CO2H)2 + VO2+ → [V{NO[CH(CH3)CO2]2}2]2− + H2O + 4 H+

Biological function

The biological function of amavadin is unknown. It has been speculated that it uses H2O2 and acts as a peroxidase to aid the regeneration of damaged tissues. Amavadin may serve as a toxin for protection of the mushroom.

Amanita muscaria contains amavadin

References

  1. 1 2 3 4 Berry, R.E.; Armstrong, E.M.; Beddoes, R.L.; Collison, D.; Ertok, S.N.; Helliwell, M.; Garner, C.D. (1999). "The Structural Characterization of Amavadin". Angew. Chem. Int. Ed. 38 (6): 795–797. doi:10.1002/(SICI)1521-3773(19990315)38:6<795::AID-ANIE795>3.0.CO;2-7. PMID 29711812.
  2. ↑ Fu, S-C.J.; Birnbaum, S.M.; Greenstein, J.P. (1954). "Influence of Optically Active Acyl Groups on the Enzymatic Hydrolysis of N-Acylated-L-amino Acids". J. Am. Chem. Soc. 76 (23): 6054–6058. doi:10.1021/ja01652a057.
  3. ↑ Kneifel, H.; Bayer, E. (1986). "Stereochemistry and total synthesis of amavadin, the naturally occurring vanadium compound of Amanita muscaria". Journal of the American Chemical Society. 108 (11): 3075–3077. doi:10.1021/ja00271a043.
  4. ↑ Armstrong, E.M.; Beddoes, R.L.; Calviou, L.J.; Charnock, J.M.; Collison, D.; Ertok, N.; Naismith, J.H.; Garner, C.D. (1993). "The Chemical Nature of Amavadin". J. Am. Chem. Soc. 115 (2): 807–808. doi:10.1021/ja00055a073.
  5. 1 2 3 Hubregtse, T.; Neeleman, E.; Maschmeyer, T.; Sheldon, R.A.; Hanefeld, U.; Arends, I.W.C.E. (2005). "The first enantioselective synthesis of the amavadin ligand and its complexation to vanadium". J. Inorg. Biochem. 99 (5): 1264–1267. doi:10.1016/j.jinorgbio.2005.02.004. PMID 15833352.
  6. ↑ Bayer, Ernst; Koch, Eckhard; Anderegg, Giorgio (1987). "Amavadin, an Example for Selective Binding of Vanadium in Nature: Studies of Its Complexation Chemistry and a New Structural Proposal". Angewandte Chemie International Edition in English. 26 (6): 545–546. doi:10.1002/anie.198705451.
  7. ↑ Garner, C.D.; Armstrong, E.M.; Berry, R.E.; Beddoes, R.L.; Collison, D.; Cooney, J.J.A.; Ertok, S.N.; Helliwell, M. (2000). "Investigations of Amavadin". J. Inorg. Biochem. 80 (1–2): 17–20. doi:10.1016/S0162-0134(00)00034-9. PMID 10885458.