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Information on EC 6.5.1.8 - 3'-phosphate/5'-hydroxy nucleic acid ligase and Organism(s) Mus musculus and UniProt Accession Q99LF4

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EC Tree
IUBMB Comments
The enzyme is a GTP- and Mn2+-dependent 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 catalyses 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 catalyses an additional reaction, hydrolysing the cyclic phosphate to a 3'-phosphate . The metazoan enzyme requires activating cofactors in order to achieve multiple turnover catalysis .
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Mus musculus
UNIPROT: Q99LF4
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The taxonomic range for the selected organisms is: Mus musculus
The expected taxonomic range for this enzyme is: Eukaryota, Archaea, Bacteria
Reaction Schemes
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(ribonucleotide)n-3'-phosphate
+
5'-hydroxy-(ribonucleotide)m
+
GTP
=
(ribonucleotide)n+m
+
GMP
+
diphosphate
+
5'-hydroxy-(ribonucleotide)m
+
=
+
+
(ribonucleotide)n-2',3'-cyclophosphate
+
5'-hydroxy-(ribonucleotide)m
+
GTP
+
H2O
=
(ribonucleotide)n+m
+
GMP
+
diphosphate
(ribonucleotide)n-2',3'-cyclophosphate
+
5'-hydroxy-(ribonucleotide)m
+
+
=
+
+
Synonyms
rtcb-1, rtcb1, rtcb rna ligase, rna-splicing ligase, trna-splicing ligase, more
SYNONYM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
rtcB
-
-
-
-
PATHWAY SOURCE
PATHWAYS
-
-
SYSTEMATIC NAME
IUBMB Comments
poly(ribonucleotide)-3'-phosphate:5'-hydroxy-poly(ribonucleotide) ligase (GMP-forming)
The enzyme is a GTP- and Mn2+-dependent 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 [6]. 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 catalyses 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 catalyses an additional reaction, hydrolysing the cyclic phosphate to a 3'-phosphate [9]. The metazoan enzyme requires activating cofactors in order to achieve multiple turnover catalysis [8].
ORGANISM
COMMENTARY hide
LITERATURE
UNIPROT
SEQUENCE DB
SOURCE
-
UniProt
Manually annotated by BRENDA team
LOCALIZATION
ORGANISM
UNIPROT
COMMENTARY hide
GeneOntology No.
LITERATURE
SOURCE
a subset of RtcB is associated with the endoplasmic reticulum
Manually annotated by BRENDA team
a subset of RtcB is associated with the nuclear envelope
Manually annotated by BRENDA team
GENERAL INFORMATION
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
physiological function
RtcB as the primary unfolded protein response RNA ligase. In RtcB knockout cells, unconventional XBP1 mRNA splicing is defective during ER stress. The RNA ligase activity of RtcB is directly required for the splicing of XBP1 mRNA
UNIPROT
ENTRY NAME
ORGANISM
NO. OF AA
NO. OF TRANSM. HELICES
MOLECULAR WEIGHT[Da]
SOURCE
SEQUENCE
LOCALIZATION PREDICTION?
RTCB_MOUSE
505
0
55249
Swiss-Prot
other Location (Reliability: 1)
REF.
AUTHORS
TITLE
JOURNAL
VOL.
PAGES
YEAR
ORGANISM (UNIPROT)
PUBMED ID
SOURCE
Lu, Y.; Liang, F.X.; Wang, X.
A synthetic biology approach identifies the mammalian UPR RNA ligase RtcB
Mol. Cell
55
758-770
2014
Mus musculus (Q99LF4)
Manually annotated by BRENDA team