Amavadin

Amavadin is a vanadium-containing anion found in three species of poisonous Amanita mushrooms: A. muscaria, A. regalis, and A. velatipes.^[1] Amavadin was first isolated and identified in 1972 by Kneifel and Bayer.^[2] This anion, which appears as a blue solution, is an eight-coordinate vanadium complex.^[1] A Ca²⁺ cation is often used to crystallize amavadin to obtain a good quality X-ray diffraction.^[1] Oxidized amavadin can be isolated as its PPh₄⁺ salt. The oxidized form contains vanadium(V), which can be used to obtain an NMR spectrum.^[3]

Preparation

The formation of amavadin begins with the formation of two tetradentate ligands.^[3]

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

Structure and properties

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

The ligand found in amavadin was first synthesized in 1954.^[4] Amavadin contains vanadium(IV). Initially, amavadin was thought to have a vanadyl, VO²⁺, center. In 1993, it was discovered by crystallographic characterization that amavadin is not a vanadyl ion compound. Instead, it is an octacoordinated vanadium(IV) complex. This complex is bonded to two tetradentate ligands derived from N-hydroxyimino-2,2'-dipropionic acid, H₃(HIDPA), ligands.^[5] The ligands coordinate through the nitrogen and the three oxygen centers.

Amavadin is a C₂-symmetric anion with a 2− charge. The two-fold 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.^[1] There are two possible diastereomers for the ligands, (S,S)-(S,S)-Δ and (S,S)-(S,S)-Λ.

The biological function of amavadin is still unknown, yet it has been thought that it uses H₂O₂ and acts as a peroxidase to aid the regeneration of damaged tissues.^[3] Amavadin may serve as a toxin for protection of the mushroom.^[6]

References

^ ^a ^b ^c ^d Berry, R.E.; Armstrong, E.M.; Beddoes, R.L.; Collison, D.; Ertok, S.N.; Helliwell, M.; Garner, C.D. “The Structural Characterization of Amavadin.” Angew. Chem. Int. Ed. 1999, 38:6, pp. 795–797. Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi: 10.1002/(SICI)1521-3773(19990315)38:6<795::AID-ANIE795>3.0.CO;2-7, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi= 10.1002/(SICI)1521-3773(19990315)38:6<795::AID-ANIE795>3.0.CO;2-7 instead..
^ Kneifel, H.; Bayer, E. “Stereochemistry and total synthesis of amavadin, the naturally occurring vanadium anion of Amanita muscaria.” J. Am. Chem. Soc. 1986, 108:11, pp. 3075–3077. Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1021/ja00271a043, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1021/ja00271a043 instead..
^ ^a ^b ^c Hubregtse, T.; Neeleman, E.; Maschmeyer, T.; Sheldon, R.A.;, Hanefeld, U.; Arends, I.W.C.E. “The first enantioselective synthesis of the amavadin ligand and its complexation to vanadium.” J. of Inorg. Biochem. 2005, 99, pp. 1264–1267. Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1016/j.jinorgbio.2005.02.004, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1016/j.jinorgbio.2005.02.004 instead..
^ Fu, S-C.J.; Birnbaum, S.M.; Greenstein, J.P. “Influence of Optically Active Acyl Groups on the Enzymatic Hydrolysis of N-Acylated-L-amino Acids.” J. Am. Chem. Soc. 1954, 76:23, pp. 6054–6058. Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi: 10.1021/ja01652a057, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi= 10.1021/ja01652a057 instead..
^ Armstrong, E.M.; Beddoes, R.L.; Calviou, L.J.; Charnock, J.M.; Collison, D.; Ertok, N.; Naismith, J.H.; Garner, C.D. “The Chemical Nature of Amavadin". J. Am. Chem. Soc. 1993, 115:2, pp. 807–808. Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi: 10.1021/ja00055a073, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi= 10.1021/ja00055a073 instead..
^ Garner, C.D.; Armstrong, E.M.; Berry, R.E.; Beddoes, R.L.; Collison, D.; Cooney, J.J.A.; Ertok, S.N.; Helliwell, M. “Investigations of Amavadin.” J. of Inorg. Biochem. 2000, 80, pp. 17–20. Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1016/S0162-0134(00)00034-9, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1016/S0162-0134(00)00034-9 instead..

[Berry-1] Berry, R.E.; Armstrong, E.M.; Beddoes, R.L.; Collison, D.; Ertok, S.N.; Helliwell, M.; Garner, C.D. “The Structural Characterization of Amavadin.” Angew. Chem. Int. Ed. 1999, 38:6, pp. 795–797. Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi: 10.1002/(SICI)1521-3773(19990315)38:6<795::AID-ANIE795>3.0.CO;2-7, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi= 10.1002/(SICI)1521-3773(19990315)38:6<795::AID-ANIE795>3.0.CO;2-7 instead..

[2] Kneifel, H.; Bayer, E. “Stereochemistry and total synthesis of amavadin, the naturally occurring vanadium anion of Amanita muscaria.” J. Am. Chem. Soc. 1986, 108:11, pp. 3075–3077. Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1021/ja00271a043, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1021/ja00271a043 instead..

[Hub-3] Hubregtse, T.; Neeleman, E.; Maschmeyer, T.; Sheldon, R.A.;, Hanefeld, U.; Arends, I.W.C.E. “The first enantioselective synthesis of the amavadin ligand and its complexation to vanadium.” J. of Inorg. Biochem. 2005, 99, pp. 1264–1267. Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1016/j.jinorgbio.2005.02.004, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1016/j.jinorgbio.2005.02.004 instead..

[4] Fu, S-C.J.; Birnbaum, S.M.; Greenstein, J.P. “Influence of Optically Active Acyl Groups on the Enzymatic Hydrolysis of N-Acylated-L-amino Acids.” J. Am. Chem. Soc. 1954, 76:23, pp. 6054–6058. Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi: 10.1021/ja01652a057, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi= 10.1021/ja01652a057 instead..

[5] Armstrong, E.M.; Beddoes, R.L.; Calviou, L.J.; Charnock, J.M.; Collison, D.; Ertok, N.; Naismith, J.H.; Garner, C.D. “The Chemical Nature of Amavadin". J. Am. Chem. Soc. 1993, 115:2, pp. 807–808. Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi: 10.1021/ja00055a073, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi= 10.1021/ja00055a073 instead..

[6] Garner, C.D.; Armstrong, E.M.; Berry, R.E.; Beddoes, R.L.; Collison, D.; Cooney, J.J.A.; Ertok, S.N.; Helliwell, M. “Investigations of Amavadin.” J. of Inorg. Biochem. 2000, 80, pp. 17–20. Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1016/S0162-0134(00)00034-9, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1016/S0162-0134(00)00034-9 instead..

[1]

[2]

[3]

[4]

[5]

[6]