Fig. 1.
Phylogenetic distribution of Pyl decoding. (A) To date, the pylRS genes encoding the pyrrolysyl-tRNA synthetase required for pyrrolysine decoding have been found in 24 organisms from archaeal and bacterial domains. Desulfobacterium autotrophicum is not included here because it possesses only a truncated version of pylSc. (B) Genomic arrangement genes required for Pyl decoding; the gene products of pylB, pylC, and pylD biosynthesize pyrrolysine, which is charged onto tRNAPyl (pylT, indicated by the black box) by its cognate pyrrolysyl-tRNA synthetase PylRS.