Pyrrolysin is a naturally occurring amino acid that is incorporated during translation into the polypeptide chains of certain proteins encoded by the genes of some methanogenic archaea . Pyrrolysin is part of some methane metabolism enzymes .
| Pyrrolysin | |
|---|---|
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| General | |
| Chem. formula | C 12 H 21 N 3 O 3 |
| Physical properties | |
| Molar mass | 255.313 g / mol |
| Classification | |
| Reg. CAS number | |
| PubChem | |
| Smiles | |
| Inchi | |
| Chebi | |
| ChemSpider | |
Pyrrolysin is a derivative of the amino acid lysine and is encoded by the UAG codon . Usually this codon acts as a stop codon . It is used less frequently than other stop codons, and if it occurs in an open reading frame, it is usually followed by other stop codons.
Next to the cluster of transfer genes for the methyl group of the archaea Methanosarcina barkeri is the pylT gene, which encodes an unusual tRNA with anticodon CUA . The adjacent pylS gene encodes a second-class aminoacyl-tRNA synthetase that attaches pyrrolysin to the tRNA product of the pylT gene. An operon containing the pylT and pylS genes is also found in the genomes of other sequenced members of the Methanosarcinaceae family. Homologs of the pylS and pylT genes were also found in the gram-positive bacterium Desulfitobacterium hafniense , although the functions of these homologs are unknown for this bacterium. [one]
It was initially shown that the pylT gene product - tRNA with anticodone (CUA) - can be "charged" with the amino acid lysine using the PylS protein. Relatively recently, it was shown that tRNA with anitcodone CUA can be “charged” with lysine in vitro by sequential interaction with lysine tRNA synthetases of the first and second class from M. barkeri . Recent data indicate that pyrrolysin is directly attached to tRNA with CUA anticodon using the protein product of the pylS gene. This means that pyrrolysin is the 22nd amino acid encoded genetically. [2]
To indicate pyrrolysin, IUPAC recommends a three-letter abbreviation Pyl and a single-letter O.
See also
- Genetic code
- Broadcast
- Selenocysteine , 21st Genetically Coded Amino Acid
Notes
- ↑ John F. Atkins and Ray Gesteland. The 22nd Amino Acid (Eng.) // Science. - 2002. - Vol. 296 , no. 5572 . - P. 1409-1410 . - DOI : 10.1126 / science.1073339 . - PMID 12029118 .
- ↑ J. Krzycki. The direct genetic encoding of pyrrolysine (neopr.) // Curr Opin Microbiol. - 2005. - T. 8 , No. 6 . - S. 706-712 . - DOI : 10.1016 / j.mib.2005.10.009 . - PMID 16256420 .