What is the mode of action of ricin?

What is the mode of action of ricin?

The bipartite molecular structure of ricin allows it to bind to the mammalian cell surface, enter via endocytic uptake, and deliver the catalytically active polypeptide into the cell cytosol where it irreversibly inhibits protein synthesis causing cell death.

What is the structure of ricin?

Structure. Ricin is a heterodimer that consists of a 32 kilodalton A chain glycoprotein (light blue) linked by a disulfide bond to a 32 kilodalton B chain glycoprotein (green). The A chain is an alpha/beta protein which contains eight alpha helices (pink) and eight beta sheets (yellow).

How can ricin be synthesized?

Biosynthesis. Ricin is synthesized in the endosperm of castor oil plant seeds. The ricin precursor protein is 576 amino acid residues in length and contains a signal peptide (residues 1–35), the ricin A chain (36–302), a linker peptide (303–314), and the ricin B chain (315–576).

Is ricin a chemical or a biological?

Ricin is one of the most toxic biological agents known—a Category B bioterrorism agent and a Schedule number 1 chemical warfare agent. Ricin toxin can be extracted from castor beans, purified and treated to form a pellet, a white powder, or dissolved in water or weak acid to be released as a liquid.

Which type of molecule is ricin?

glycoprotein
Ricin is a glycoprotein, with several carbohydrate chains on its surface, and it is stabilized by several disulfide linkages.

What does ricin do to ribosomes?

Ricin is a ribosome-inactivating protein — it irrevocably damages the ribosomes that carry out protein synthesis in cells. The ribosome-inactivating proteins found in the castor bean plant are extremely powerful, and ricin poisoning can do serious damage to major organs.

When was ricin a biological weapon?

Since ricin-poisoning was relatively rare, no particular efforts had been made to find an ad hoc treatment or take preventive measures until the 90’s, when ricin was recognized as a possible threat in biological warfare.

What is the other name for ricin?

ricin, toxic protein (toxalbumin) occurring in the beanlike seeds of the castor-oil plant (Ricinus communis). Ricin, discovered in 1888 by German scientist Peter Hermann Stillmark, is one of the most toxic substances known.

What means ricin?

: a poisonous protein in the castor bean.

What is ricin as a protein?

Ricin is a heterodimeric protein produced in the seeds of the castor oil plant (Ricinus communis). It is exquisitely potent to mammalian cells, being able to fatally disrupt protein synthesis by attacking the Achilles heel of the ribosome.

What organelle is affected by ricin?

Ricin belongs to a family of functionally related toxins, collectively referred to as ribosome inactivating proteins (RIPs), which disable ribosomes and halt protein synthesis.

Who developed ricin?

scientist Peter Hermann Stillmark
ricin, toxic protein (toxalbumin) occurring in the beanlike seeds of the castor-oil plant (Ricinus communis). Ricin, discovered in 1888 by German scientist Peter Hermann Stillmark, is one of the most toxic substances known.

How is ricin detected?

Public health laboratories that are part of CDC’s Laboratory Response Network (LRN) use rapid detection tests for environmental samples. Some LRN laboratories can test clinical urine samples for the presence of ricinine, an indicator of ricin exposure.

How does ricin enter the cell?

Ricin, in common with other A-B family plant and bacterial toxins, enters mammalian cells by endocytosis after binding to cell surface components that inadvertently act as toxin receptors.

How does ricin affect protein synthesis?

Ricin A chain (RTA) inhibits protein synthesis by removing a specific adenine from the highly conserved α-sarcin/ricin loop in the large rRNA. Expression of RTA with its own signal sequence in yeast resulted in its translocation into the endoplasmic reticulum (ER) and subsequent glycosylation.

Is there a vaccine for ricin?

There is no approved vaccine for ricin. Ricin contains a lectin-binding B chain and a ribotoxic A chain (RTA).

What is the mechanism of action of ricin?

Ricin is an abundant protein component of Ricinus communis seeds (castor beans) that is exquisitely toxic to mammalian cells. It consists of an enzymic polypeptide that catalyzes the N-glycosidic cleavage of a specific adenine residue from 28S ribosomal RNA, joined by a single disulfide bond to a galactose (cell)-binding lectin.

What is the function of ricin in castor beans?

Ricin is an abundant protein component of Ricinus communis seeds (castor beans) that is exquisitely toxic to mammalian cells. It consists of an enzymic polypeptide that catalyzes the N-glycosidic cleavage of a specific adenine residue from 28S ribosomal RNA, joined by a single disulfide bond to a ga …

What type of protein is ricin?

ABSTRACT Ricin is an abundant protein component ofRicinus communisseeds (castor beans) that is exqui- sitely toxic to mammalian cells. It consists of an enzymic polypeptide that catalyzes the N-glycosidic cleavage of a

Why is modified ricin being used in transgenic organisms?

Because of its cytotoxic potency, modified ricin is being used for the selective killing of unwanted cells and for the toxigenic ablation of cell lineages in transgenic organisms. Publication types Review MeSH terms Animals Endocytosis