ENZYME entry: EC 188.8.131.52
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|3'-phosphate/5'-hydroxy nucleic acid ligase.
- (Ribonucleotide)(n)-3'-phosphate + 5'-hydroxy-(ribonucleotide)(m) + GTP <=> (ribonucleotide)(n+m) + GMP + diphosphate
- (Ribonucleotide)(n)-2',3'-cyclophosphate + 5'-hydroxy-(ribonucleotide)(m) + GTP + H(2)O <=> (ribonucleotide)(n+m) + GMP + diphosphate (overall reaction)
- The enzyme is a 3'-5' nucleic acid ligase with the ability to join
RNA with 3'-phosphate or 2',3'-cyclic-phosphate ends to RNA with
- It can also join DNA with 3'-phosphate ends to DNA with 5'-hydroxy
ends, provided the DNA termini are unpaired.
- The enzyme is found in members of all three kingdoms of life, and is
essential in metazoa for the splicing of intron-containing tRNAs.
- The reaction follows a three-step mechanism with initial activation
of the enzyme by GTP hydrolysis, forming a phosphoramide bond between
the guanylate and a histidine residue.
- The guanylate group is transferred to the 3'-phosphate terminus of
the substrate, forming the capped structure (DNA/RNA)-
- When a suitable 5'-OH end is available, the enzyme catalyzes an
attack of the 5'-OH on the capped end to form a 3'-5' phosphodiester
splice junction, releasing the guanylate.
- When acting on an RNA 2',3'-cyclic-phosphate, the enzyme cayalyses an
additional reaction, hydrolyzing the cyclic phosphate to a
- The metazoan enzyme requires activating cofactors in order to achieve
multiple turnover catalysis.
|PRIAM enzyme-specific profiles||184.108.40.206|
|KEGG Ligand Database for Enzyme Nomenclature||220.127.116.11|
|IUBMB Enzyme Nomenclature||18.104.22.168|
|MEDLINE||Find literature relating to 22.214.171.124|
entries corresponding to 6.5.1.-
entries corresponding to 6.5.-.-
entries corresponding to 6.-.-.-