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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_CULQUP0DX92, RTCB1_ECOS1B0EAV2, RTCB1_ENTDS
C4M244, RTCB1_ENTH1B0XKF3, RTCB2_CULQUP0DX91, RTCB2_ECOS1
B0EIW5, RTCB2_ENTDSC4M6T2, RTCB2_ENTH1Q17FP1, RTCB_AEDAE
Q9YB37, RTCB_AERPEQ7Q412, RTCB_ANOGAO29399, RTCB_ARCFU
Q5E9T9, RTCB_BOVINC3YN79, RTCB_BRAFLA8QC60, RTCB_BRUMA
P90838, RTCB_CAEELA8JC00, RTCB_CHLREQ6NZS4, RTCB_DANRE
Q54Y09, RTCB_DICDIQ9VIW7, RTCB_DROMEP46850, RTCB_ECOLI
Q9Y3I0, RTCB_HUMANQ4R6X4, RTCB_MACFAQ58095, RTCB_METJA
Q8TUS2, RTCB_METKAQ6LXF9, RTCB_METMPO27634, RTCB_METTH
C1E9Y5, RTCB_MICCCC1MI97, RTCB_MICPCA9UXG6, RTCB_MONBE
Q99LF4, RTCB_MOUSEP59975, RTCB_MYCBOP9WGW4, RTCB_MYCTO
P9WGW5, RTCB_MYCTUQ74MJ0, RTCB_NANEQA7RKF6, RTCB_NEMVE
A4S3S3, RTCB_OSTLUQ00ZY2, RTCB_OSTTAA9CB42, RTCB_PAPAN
Q19PY3, RTCB_PIGQ4YUZ9, RTCB_PLABAQ8IIU6, RTCB_PLAF7
B3L4K9, RTCB_PLAKHQ7RI54, RTCB_PLAYOQ9V168, RTCB_PYRAB
Q8ZY09, RTCB_PYRAEQ8U0H4, RTCB_PYRFUO59245, RTCB_PYRHO
Q6AYT3, RTCB_RATB8LBM8, RTCB_THAPSQ4U923, RTCB_THEAN
Q5JCZ1, RTCB_THEKOQ4N1R8, RTCB_THEPAB3RID0, RTCB_TRIAD
Q561P3, RTCB_XENTR

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