Pyrrolysine

Pyrrolysine is a genetically encoded amino acid used by some methane-producing archaea and bacteria. Its dedicated translation machinery inserts it into proteins at UAG stop codons.

PylS: PylS is the pyrrolysyl-tRNA synthetase that attaches pyrrolysine to its dedicated transfer RNA. This enzyme charges the tRNA that delivers pyrrolysine to the ribosome.
UAG codon: UAG is an mRNA codon that normally signals termination of protein synthesis. Pyrrolysine is inserted where UAG ordinarily ends translation.
Noncanonical amino acid: A noncanonical amino acid is a protein-incorporated amino acid outside the standard set of twenty. Pyrrolysine is a naturally occurring example of this broader class.
Methylamine methyltransferase: Methylamine methyltransferases transfer a methyl group from methylamine to a corrinoid protein. Pyrrolysine occurs at the active site of several enzymes in this family.
Jillian P. H. S. Lee: Jillian P. H. S. Lee is a biochemist who co-discovered pyrrolysine in methane-producing archaea. Lee was among the researchers who identified pyrrolysine in methylamine-processing enzymes.
tRNA-Pyl: tRNA-Pyl is the transfer RNA that recognizes UAG codons and carries pyrrolysine during translation. Its anticodon lets pyrrolysine enter a growing protein at UAG.
Genetic code: The genetic code maps nucleotide codons to amino acids and translation signals. Pyrrolysine is a rare exception to UAG's usual stop assignment.
Genetic code reprogramming: Genetic code reprogramming changes the meaning of codons to incorporate selected amino acids into proteins. Pyrrolysine's UAG system can be adapted to install other amino acids.
Monomethylamine methyltransferase: Monomethylamine methyltransferase is a pyrrolysine-containing enzyme that transfers a methyl group from monomethylamine. Its active-site pyrrolysine helps accommodate and process its methylamine substrate.
Joseph A. Krzycki: Joseph A. Krzycki is a microbiologist whose research includes pyrrolysine and archaeal methylamine metabolism. His work helped characterize pyrrolysine's biological role and decoding system.

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Proteinogenic amino acidBroader topic: It is the rare twenty-second genetically encoded proteinogenic amino acid.