page_title: Ribosomally synthesized and post-translationally modified peptides
section_title: Amatoxins and phallotoxins
hierarchical_section_title: Ribosomally synthesized and post-translationally modified peptides / Classifications / Amatoxins and phallotoxins
caption_attribution_description: English: The structure of a-amanitin, with posttranslational modifications particular to the amatoxins and phallotoxins shown in red.
context_page_description: Ribosomally synthesized and post-translationally modified peptides, also known as ribosomal natural products, are a diverse class of natural products of ribosomal origin. Consisting of more than 20 sub-classes, RiPPs are produced by a variety of organisms, including prokaryotes, eukaryotes, and archaea, and they possess a wide range of biological functions.
  As a consequence of the falling cost of genome sequencing and the accompanying rise in available genomic data, scientific interest in RiPPs has increased in the last few decades. Because the chemical structures of RiPPs are more closely predictable from genomic data than are other natural products, their presence in sequenced organisms can, in theory, be identified rapidly. This makes RiPPs an attractive target of modern natural product discovery efforts.
context_section_description: Amatoxins and phallotoxins are 8- and 7-membered natural products, respectively, characterized by N-to-C cyclization in addition to a tryptathionine motif derived from the crosslinking of Cys and Trp. The amatoxins and phallotoxins also differ from other RiPPs based on the presence of a C-terminal recognition sequence in addition to the N-terminal leader peptide. α-Amanitin, an amatoxin, has a number of posttranslational modifications in addition to macrocyclization and formation of the tryptathionine bridge: oxidation of the tryptathionine leads to the presence of a sulfoxide, and numerous hydroxylations decorate the natural product. As an amatoxin, α-amanitin is an inhibitor of RNA polymerase II.
caption: The structure of α-amanitin, with posttranslational modifications particular to the amatoxins and phallotoxins shown in red.
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