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ENZYME

ENZYME entry: EC 6.5.1.8

Accepted Name
3'-phosphate/5'-hydroxy nucleic acid ligase
Reaction catalysed
  • a 3'-end 3'-phospho-ribonucleotide-RNA + a 5'-end dephospho-ribonucleoside-RNA + GTP <=> a ribonucleotidyl-ribonucleotide-RNA + diphosphate + GMP
  • a 3'-end 2',3'-cyclophospho-ribonucleotide-RNA + a 5'-end dephospho-ribonucleoside-RNA + GTP + H2O <=> a ribonucleotidyl-ribonucleotide-RNA + diphosphate + GMP + H(+)
Comment(s)
  • 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 5'-hydroxy ends.
  • 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]- 3'-(5'-diphosphoguanosine).
  • 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 catalyzes an additional reaction, hydrolyzing the cyclic phosphate to a 3'-phosphate.
  • The metazoan enzyme requires activating cofactors in order to achieve multiple turnover catalysis.
Cross-references
BRENDA6.5.1.8
EC2PDB6.5.1.8
ExplorEnz6.5.1.8
PRIAM enzyme-specific profiles6.5.1.8
KEGG Ligand Database for Enzyme Nomenclature6.5.1.8
IUBMB Enzyme Nomenclature6.5.1.8
IntEnz6.5.1.8
MEDLINEFind literature relating to 6.5.1.8
MetaCyc6.5.1.8
Rhea expert-curated reactions6.5.1.8
UniProtKB/Swiss-Prot
B0WCT9, RTCB1_CULQUB0EAV2, RTCB1_ENTDSC4M244, RTCB1_ENTH1
B0XKF3, RTCB2_CULQUB0EIW5, RTCB2_ENTDSC4M6T2, RTCB2_ENTH1
Q17FP1, RTCB_AEDAEQ9YB37, RTCB_AERPEQ7Q412, RTCB_ANOGA
O29399, RTCB_ARCFUQ5E9T9, RTCB_BOVINC3YN79, RTCB_BRAFL
A8QC60, RTCB_BRUMAP90838, RTCB_CAEELA8JC00, RTCB_CHLRE
Q6NZS4, RTCB_DANREQ54Y09, RTCB_DICDIQ9VIW7, RTCB_DROME
P46850, RTCB_ECOLIQ9Y3I0, RTCB_HUMANQ4R6X4, RTCB_MACFA
Q58095, RTCB_METJAQ8TUS2, RTCB_METKAQ6LXF9, RTCB_METMP
O27634, RTCB_METTHC1E9Y5, RTCB_MICCCC1MI97, RTCB_MICPC
A9UXG6, RTCB_MONBEQ99LF4, RTCB_MOUSEP59975, RTCB_MYCBO
P9WGW4, RTCB_MYCTOP9WGW5, RTCB_MYCTUQ74MJ0, RTCB_NANEQ
A7RKF6, RTCB_NEMVEA4S3S3, RTCB_OSTLUQ00ZY2, RTCB_OSTTA
A9CB42, RTCB_PAPANQ19PY3, RTCB_PIGQ4YUZ9, RTCB_PLABA
Q8IIU6, RTCB_PLAF7B3L4K9, RTCB_PLAKHQ7RI54, RTCB_PLAYO
Q9V168, RTCB_PYRABQ8ZY09, RTCB_PYRAEQ8U0H4, RTCB_PYRFU
O59245, RTCB_PYRHOQ6AYT3, RTCB_RATB8LBM8, RTCB_THAPS
Q4U923, RTCB_THEANQ5JCZ1, RTCB_THEKOQ4N1R8, RTCB_THEPA
B3RID0, RTCB_TRIADQ561P3, RTCB_XENTR

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All ENZYME / UniProtKB/Swiss-Prot entries corresponding to 6.5.1.-
All ENZYME / UniProtKB/Swiss-Prot entries corresponding to 6.5.-.-
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