Proamanullin

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Proamanullin
Proamanullin structure.png
Names
Other names
2-L-Proline-3-isoleucine-alpha-amanitin
Identifiers
3D model (JSmol)
ChemSpider
PubChem CID
Properties
C39H54N10O11S
Molar mass 870.97 g/mol
Appearance Colorless, odorless
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Promanullin is a cyclic nonribosomal peptide. It is an amatoxin, all of which are found in the mushroom genus Amanita .

Cyclic compound Molecule with a ring of bonded atoms

A cyclic compound is a term for a compound in the field of chemistry in which one or more series of atoms in the compound is connected to form a ring. Rings may vary in size from three to many atoms, and include examples where all the atoms are carbon, none of the atoms are carbon, or where both carbon and non-carbon atoms are present. Depending on the ring size, the bond order of the individual links between ring atoms, and their arrangements within the rings, carbocyclic and heterocyclic compounds may be aromatic or non-aromatic, in the latter case, they may vary from being fully saturated to having varying numbers of multiple bonds between the ring atoms. Because of the tremendous diversity allowed, in combination, by the valences of common atoms and their ability to form rings, the number of possible cyclic structures, even of small size numbers in the many billions.

Nonribosomal peptides (NRP) are a class of peptide secondary metabolites, usually produced by microorganisms like bacteria and fungi. Nonribosomal peptides are also found in higher organisms, such as nudibranchs, but are thought to be made by bacteria inside these organisms. While there exist a wide range of peptides that are not synthesized by ribosomes, the term nonribosomal peptide typically refers to a very specific set of these as discussed in this article.

Amatoxin is the collective name of a subgroup of at least eight related toxic compounds found in several genera of poisonous mushrooms, most notably the death cap and several other members of the genus Amanita, as well as some Conocybe, Galerina and Lepiota mushroom species. Amatoxins are lethal in even small doses. Unlike many ingested poisons they are not destroyed by heat so cooking the poisonous mushrooms does not diminish their lethality which can be as little as eating half a mushroom.

Contents

Toxicology

Like other amatoxins, proamanullin is an inhibitor of RNA polymerase II. Promanullin has a specific attraction to the enzyme RNA polymerase II. Upon ingestion, it binds to the RNA polymerase II enzyme, effectively causing cytolysis of hepatocytes (liver cells). [1]

RNA polymerase II type of protein

RNA polymerase II is a multiprotein complex. It is one of the three RNAP enzymes found in the nucleus of eukaryotic cells. It catalyzes the transcription of DNA to synthesize precursors of mRNA and most snRNA and microRNA. A 550 kDa complex of 12 subunits, RNAP II is the most studied type of RNA polymerase. A wide range of transcription factors are required for it to bind to upstream gene promoters and begin transcription.

Cytolysis The rupture of cell membranes and the loss of cytoplasm.

Cytolysis, or osmotic lysis, occurs when a cell bursts due to an osmotic imbalance that has caused excess water to diffuse into the cell. Water can enter the cell by diffusion through the cell membrane or through selective membrane channels called aquaporins, which greatly facilitate the flow of water. It occurs in a hypotonic environment, where water moves into the cell by osmosis and causes its volume to increase to the point where the volume exceeds the membrane's capacity and the cell bursts. The presence of a cell wall prevents the membrane from bursting, so cytolysis only occurs in animal and protozoa cells which do not have cell walls. The reverse process is plasmolysis.

Hepatocyte cell type

A hepatocyte is a cell of the main parenchymal tissue of the liver. Hepatocytes make up 70-85% of the liver's mass. These cells are involved in:

See also

Related Research Articles

Polymerase rna polymerase

A polymerase is an enzyme that synthesizes long chains of polymers or nucleic acids. DNA polymerase and RNA polymerase are used to assemble DNA and RNA molecules, respectively, by copying a DNA template strand using base-pairing interactions or RNA by half ladder replication.

<i>Amanita phalloides</i> Poisonous fungus in the family Amanitaceae, widely distributed across Europe

Amanita phalloides, commonly known as the death cap, is a deadly poisonous basidiomycete fungus, one of many in the genus Amanita. Widely distributed across Europe, but now sprouting in other parts of the world, A. phalloides forms ectomycorrhizas with various broadleaved trees. In some cases, the death cap has been introduced to new regions with the cultivation of non-native species of oak, chestnut, and pine. The large fruiting bodies (mushrooms) appear in summer and autumn; the caps are generally greenish in colour with a white stipe and gills. Cap colour is variable, including white forms, and thus not a reliable identifier.

Destroying angel deadly poisonous fungus

The name destroying angel applies to several similar, closely related species of deadly all-white mushrooms in the genus Amanita. They are Amanita bisporigera and A. ocreata in eastern and western North America, and A. virosa in Europe. Another very similar species, A. verna or fool's mushroom, was first described in France.

<i>alpha</i>-Amanitin chemical compound

alpha-Amanitin or α-amanitin is a cyclic peptide of eight amino acids. It is possibly the most deadly of all the amatoxins, toxins found in several species of the mushroom genus Amanita, one being the death cap as well as the destroying angel, a complex of similar species, principally A. virosa and A. bisporigera. It is also found in the mushrooms Galerina marginata and Conocybe filaris. The oral LD50 of amanitin is approximately 0.1 mg/kg for rats.

<i>Amanita virosa</i> species of fungus

Amanita virosa, commonly known in Europe as the destroying angel, is a deadly poisonous basidiomycete fungus, one of many in the genus Amanita. Occurring in Europe, A. virosa associates with various deciduous and coniferous trees. The large fruiting bodies appear in summer and autumn; the caps, stipes and gills are all white in colour.

General transcription factor

General transcription factors (GTFs), also known as basal transcriptional factors, are a class of protein transcription factors that bind to specific sites (promoter) on DNA to activate transcription of genetic information from DNA to messenger RNA. GTFs, RNA polymerase, and the mediator constitute the basic transcriptional apparatus that first bind to the promoter, then start transcription. GTFs are also intimately involved in the process of gene regulation, and most are required for life.

Amanin a cyclic peptide

Amanin is a cyclic peptide. It is one of the amatoxins, all of which are found in several members of the mushroom genus Amanita.

<i>Amanita ocreata</i> Species of poisonous fungus in the genus Amanita endemic to western North America

Amanita ocreata, commonly known as the death angel, destroying angel, angel of death or more precisely western North American destroying angel, is a deadly poisonous basidiomycete fungus, one of many in the genus Amanita. Occurring in the Pacific Northwest and California floristic provinces of North America, A. ocreata associates with oak trees. The large fruiting bodies generally appear in spring; the cap may be white or ochre and often develops a brownish centre, while the stipe, ring, gill and volva are all white.

<i>beta</i>-Amanitin chemical compound

beta-Amanitin or β-amanitin is a cyclic peptide comprising eight amino acids. It is part of a group of toxins called amatoxins, which can be found in several mushrooms belonging to the genus Amanita. Some examples are the death cap and members of the destroying angel complex, which includes A. virosa and A. bisporigera. Due to the presence of α-amanitin, β-amanitin, γ-amanitin and ε-amanitin these mushrooms are highly lethal to human beings.

Gamma-Amanitin a cyclic peptide

gamma-Amanitin or γ-amanitin is a cyclic peptide of eight amino acids. It is an amatoxin, a group of toxins isolated from and found in several members of the mushroom genus Amanita, one being the death cap as well as the destroying angel, a complex of similar species, principally A. virosa and A. bisporigera. The compound is highly toxic, inhibits RNA polymerase II, disrupts synthesis of mRNA, and can be fatal.

In enzymology, a polynucleotide adenylyltransferase is an enzyme that catalyzes the chemical reaction

In enzymology, a [RNA-polymerase]-subunit kinase is an enzyme that catalyzes the chemical reaction

Amanullin a cyclic peptide

Amanullin is a cyclic peptide. It is an amatoxin, all of which are found in several members of the mushroom genus Amanita. The oral LD50 of amanullin is approximately 20 mg/kg in mice; however, it is non-toxic in humans.

epsilon-Amanitin chemical compound

epsilon-Amanitin or ε-amanitin is a cyclic peptide. It is an amatoxin, all of which are found in several members of the mushroom genus Amanita. The oral LD50 of ε-amanitin is approximately 0.1 mg/kg.

Amanullinic acid chemical compound

Amanullinic acid is a cyclic nonribosomal peptide. It is an amatoxin, all of which are found in several members of the mushroom genus Amanita. Amanullinic acid is relatively non-toxic( oral LD50 >20 mg/kg in mice).

Amaninamide a cyclic peptide

Amaninamide is a cyclic peptide. It is one of the amatoxins, all of which are found in several members of the mushroom genera Amanita, Lepiota and Galerina. It differs from alpha-amanitin in lacking the hydroxyl group on tryptophan. This alters its UV absorption spectrum but not its toxicity.

RNA polymerase V is a multisubunit plant specific RNA polymerase found in nucleus. Together with RNA polymerase IV required for normal function and biogenesis of small interfering RNA (siRNA). Pol V is involved in siRNA-directed DNA methylation pathway which leads to heterochromatic silencing.

References

  1. ↑ Cochet-Meilhac M, Chambon P (June 1974). "Animal DNA-dependent RNA polymerases. 11. Mechanism of the inhibition of RNA polymerases B by amatoxins". Biochim. Biophys. Acta. 353 (2): 160–84. doi:10.1016/0005-2787(74)90182-8. PMID   4601749.
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