PYLIS downstream sequence

In biology, the PYLIS downstream sequence (PYLIS: pyrrolysine insertion sequence) is a stem-loop structure that appears on some mRNA sequences. This structural motif was previously thought to cause the UAG (amber) stop codon to be translated to the amino acid pyrrolysine instead of ending the protein translation.^[1][2][3] However, it has been shown that PYLIS has no effect upon the efficiency of the UAG suppression,^[4] hence even its name is, in fact, incorrect.

Pyrrolysine insertion sequence 1 (mtmB)
Predicted secondary structure of PYLIS 1 RNA.
Identifiers
Symbol	PYLIS_1
Rfam	RF01982
Other data
RNA type	Presumed cis-regulatory element
Domain(s)	Archaea and Bacteria
PDB structures	PDBe

Pyrrolysine insertion sequence mtbB
Identifiers
Symbol	PYLIS_2
Rfam	RF02509
Other data
PDB structures	PDBe

Pyrrolysine insertion sequence mttB
Identifiers
Symbol	PYLIS_3
Rfam	RF02510
Other data
PDB structures	PDBe

Pyrrolysine insertion sequence TetR
Identifiers
Symbol	PYLIS_4
Rfam	RF02511
Other data
PDB structures	PDBe

Pyrrolysine insertion sequence transposase 1
Identifiers
Symbol	PYLIS_5
Rfam	RF02512
Other data
PDB structures	PDBe

Pyrrolysine insertion sequence transposase 2
Identifiers
Symbol	PYLIS_6
Rfam	RF02513
Other data
PDB structures	PDBe

See also

• SECIS element