amavadin
{{Chembox
| verifiedrevid = 413963787
| ImageFile = Amavadin.svg
| ImageSize = 200px
| ImageFile1 = Amavadin-from-xtal-1999-3D-balls.png
| ImageName1 = Ball-and-stick model of the amavadin dianion
| IUPACName = bis[N-[(1S)-1-(carboxy-κO)ethyl]-N-(hydroxy-κO)-L-alaninato(2-)-.κN,κO]-vanadium
| OtherNames =
|Section1={{Chembox Identifiers
| CASNo_Ref = {{cascite|correct|??}}
| CASNo = 12705-99-6
| PubChem = 119025631
| PubChem_Comment = dihydric acid
| ChemSpiderID = 52085372
| ChemSpiderID_Comment = dihydric acid
| UNII = 5J3H8J7S42
| SMILES = CC(C(=O)[O-])N(C(C)C(=O)[O-])[O-].CC(C(=O)[O-])N(C(C)C(=O)[O-])[O-].[V+4]
| StdInChI=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
| StdInChIKey = JFEAKSQUSDDXGF-UHFFFAOYSA-J
}}
|Section2={{Chembox Properties
| Formula = [V{NO[CH(CH3)CO2]2}2]2−
| MolarMass = 398.94 g/mol
| Appearance = Light blue in solution
| Density =
| MeltingPt =
| BoilingPt =
| Solubility = }}
|Section3={{Chembox Hazards
| MainHazards =
| FlashPt =
| AutoignitionPt = }}
}}
Amavadin is a vanadium-containing anion found in three species of poisonous Amanita mushrooms: A. muscaria, A. regalis, and A. velatipes.{{cite journal |author1=Berry, R.E. |author2=Armstrong, E.M. |author3=Beddoes, R.L. |author4=Collison, D. |author5=Ertok, S.N. |author6=Helliwell, M. |author7=Garner, C.D. | title = The Structural Characterization of Amavadin | journal = Angew. Chem. Int. Ed. | year = 1999 | volume = 38 | issue = 6 | pages = 795–797 | doi = 10.1002/(SICI)1521-3773(19990315)38:6<795::AID-ANIE795>3.0.CO;2-7 | pmid=29711812| doi-access=free }} Amavadin was first isolated and identified in 1972 by Kneifel and Bayer.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. {{Cite journal| first1 = H.| first2 = E.| title = Stereochemistry and total synthesis of amavadin, the naturally occurring vanadium compound of Amanita muscaria| last1 = Kneifel| journal = Journal of the American Chemical Society| volume = 108| issue = 11| pages = 3075–3077| year = 1986| doi = 10.1021/ja00271a043| last2 = Bayer}}. This anion, which appears as a blue solution, 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 can be used to obtain an NMR spectrum.{{cite journal |author1=Hubregtse, T. |author2=Neeleman, E. |author3=Maschmeyer, T. |author4=Sheldon, R.A. |author5=Hanefeld, U. |author6=Arends, I.W.C.E. | title = The first enantioselective synthesis of the amavadin ligand and its complexation to vanadium | journal = J. Inorg. Biochem. | year = 2005 | volume = 99 | pages = 1264–1267 | doi = 10.1016/j.jinorgbio.2005.02.004 | pmid=15833352 | issue = 5}}
Preparation
The formation of amavadin begins with the formation of two tetradentate ligands.
:2 HON(CH(CH3)CO2H)2 + VO2+ → [V{NO[CH(CH3)CO2]2}2]2− + H2O + 4 H+
Structure and properties
The ligand found in amavadin was first synthesized in 1954.{{cite journal |author1=Fu, S-C.J. |author2=Birnbaum, S.M. |author3=Greenstein, J.P. | title = Influence of Optically Active Acyl Groups on the Enzymatic Hydrolysis of N-Acylated-L-amino Acids | journal = J. Am. Chem. Soc. | year = 1954 | volume = 76 | issue = 23 | pages = 6054–6058 | doi = 10.1021/ja01652a057}} 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.{{cite journal |author1=Armstrong, E.M. |author2=Beddoes, R.L. |author3=Calviou, L.J. |author4=Charnock, J.M. |author5=Collison, D. |author6=Ertok, N. |author7=Naismith, J.H. |author8=Garner, C.D. | title = The Chemical Nature of Amavadin | journal = J. Am. Chem. Soc. | year = 1993 | volume = 115 | issue = 2 | pages = 807–808 | doi = 10.1021/ja00055a073}} The ligands coordinate through the nitrogen and the three oxygen centers.
Amavadin is a C2-symmetric anion with a 2− 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.
Biological function
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. Amavadin may serve as a toxin for protection of the mushroom.{{cite journal |author1=Garner, C.D. |author2=Armstrong, E.M. |author3=Berry, R.E. |author4=Beddoes, R.L. |author5=Collison, D. |author6=Cooney, J.J.A. |author7=Ertok, S.N. |author8=Helliwell, M. | title = Investigations of Amavadin | journal = J. Inorg. Biochem. | year = 2000 | volume = 80 | pages = 17–20 | doi=10.1016/S0162-0134(00)00034-9 | pmid=10885458 | issue = 1–2}}
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