All amatoxins contain the same 8 amino acids in the same sequence. They are thus conserved.
The correct answer and explanation is:
Amatoxins are a group of cyclic peptides, primarily found in certain species of mushrooms, most notably Amanita species, including the notorious Amanita phalloides (death cap mushroom). These toxins are highly poisonous and are responsible for the toxic effects seen in mushroom poisoning.
The statement that all amatoxins contain the same eight amino acids in the same sequence refers to their primary structure. The primary structure of a protein or peptide is its unique sequence of amino acids, which determines its specific function and activity. In the case of amatoxins, this conserved sequence of eight amino acids forms the backbone of their molecular structure, making them structurally similar across different types of amatoxins.
The conservation of this sequence is significant because it is the specific arrangement of these amino acids that allows amatoxins to bind to and inhibit RNA polymerase II, an essential enzyme in eukaryotic cells. This enzyme is involved in the transcription of DNA into RNA, and its inhibition leads to the disruption of protein synthesis, causing cellular damage. As a result, the toxicity of amatoxins is largely due to their ability to interfere with gene expression and cellular function.
The conservation of the amino acid sequence across different forms of amatoxins suggests that this sequence is critical for their function. Even slight changes to the sequence could potentially alter their toxicity or effectiveness in binding to RNA polymerase II. This is why the sequence is highly conserved in nature, ensuring that the toxin retains its deadly effects.
Overall, the conservation of these eight amino acids in amatoxins underscores the importance of their structure-function relationship in their toxicity. It also explains why these toxins are potent even in small amounts, as they are highly effective in disrupting cellular processes.
