English
 
User Manual Privacy Policy Disclaimer Contact us
  Advanced SearchBrowse

Item

ITEM ACTIONSEXPORT

Released

Journal Article

Virotoxins: actin-binding cyclic peptides of Amanita virosa mushrooms

MPS-Authors
/persons/resource/persons92864

Faulstich,  Heinz
Department of Molecular Cell Research, Max Planck Institute for Medical Research, Max Planck Society;

/persons/resource/persons205933

Buku,  Angeliki
Max Planck Institute for Medical Research, Max Planck Society;

/persons/resource/persons211076

Bodenmüller,  Heinz
Max Planck Institute for Medical Research, Max Planck Society;

/persons/resource/persons197838

Wieland,  Theodor
Max Planck Institute for Medical Research, Max Planck Society;

Fulltext (public)
There are no public fulltexts stored in PuRe
Supplementary Material (public)
There is no public supplementary material available
Citation

Faulstich, H., Buku, A., Bodenmüller, H., & Wieland, T. (1980). Virotoxins: actin-binding cyclic peptides of Amanita virosa mushrooms. Biochemistry, 19(14), 3334-3343. doi:10.1021/bi00555a036.


Cite as: http://hdl.handle.net/21.11116/0000-0004-875A-F
Abstract
Virotoxins are toxic peptides singularly found in Amanita virosa mushrooms. After purification and resolution by high-pressure liquid chromatography, the main component, viroisin, was selectively cleaved and submitted to Edman degradation. The structure could be completely elucidated and was in part found to be the same as in phallotoxins. Differing from the phallotoxins, however, virotoxins are monocyclic peptides and contain D-serine instead of L-cysteine. In addition, two amino acids were detected in virotoxins which thus far have not been found in nature: 2,3-trans-3,4-dihydroxy-L-proline and 2'-(methylsulfonyl)-L-tryptophan. The biological activity of viroisin is comparable to that of the phallotoxins: e.g., with 2.5 mg of viroisin per kg (white mouse), 50% of the animals die within 2-5 h by hemorrhagia of the liver. Also, on the molecular level, the virotoxins behave similar to the phallotoxins. Thus, viroisin binds to rabbit muscle actin as proved by difference UV spectroscopy. With an apparent equilibrium dissociation constant KD approximately 2 x 10(-8) M, the affinity of viroisin is very similar to that of phalloidin. However, the flexibility of the monocyclic structure and the presence of two additional hydroxy groups in the virotoxins suggest a different mode of interaction with actin. While there is proof that the bicyclic phallotoxins possess a rigid binding site, the virotoxins may adopt the biologically active conformation by an induced-fit mechanism upon contact with actin.