Enzymes
| UniProtKB help_outline | 5,038 proteins |
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Namehelp_outline
a 5'-end (N7-methyl 5'-triphosphoguanosine)-ribonucleoside in snRNA
Identifier
RHEA-COMP:19085
Reactive part
help_outline
- Name help_outline a 5'-(N7-methyl 5'-triphosphoguanosine)-ribonucleoside residue Identifier CHEBI:156461 Charge -2 Formula C16H22N5O17P3R SMILEShelp_outline C1(=O)NC(=NC2=C1[N+](=CN2[C@@H]3O[C@H](COP(OP(OP(OC[C@H]4O[C@H]([C@@H]([C@@H]4O*)O)*)(=O)[O-])(=O)[O-])(=O)[O-])[C@@H](O)[C@H]3O)C)N 2D coordinates Mol file for the small molecule Search links Involved in 19 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline S-adenosyl-L-methionine Identifier CHEBI:59789 Charge 1 Formula C15H23N6O5S InChIKeyhelp_outline MEFKEPWMEQBLKI-AIRLBKTGSA-O SMILEShelp_outline C[S+](CC[C@H]([NH3+])C([O-])=O)C[C@H]1O[C@H]([C@H](O)[C@@H]1O)n1cnc2c(N)ncnc12 2D coordinates Mol file for the small molecule Search links Involved in 938 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
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Namehelp_outline
a 5'-end (N2,N7-dimethyl 5'-triphosphoguanosine)-ribonucleoside in snRNA
Identifier
RHEA-COMP:19087
Reactive part
help_outline
- Name help_outline a 5'-(N2,N7-dimethyl 5'-triphosphoguanosine)-ribonucleoside residue Identifier CHEBI:172880 Charge -2 Formula C17H24N5O17P3R SMILEShelp_outline C1(=O)NC(=NC2=C1[N+](=CN2[C@@H]3O[C@H](COP(OP(OP(OC[C@H]4O[C@H]([C@@H]([C@@H]4O*)O)*)(=O)[O-])(=O)[O-])(=O)[O-])[C@@H](O)[C@H]3O)C)NC 2D coordinates Mol file for the small molecule Search links Involved in 4 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline S-adenosyl-L-homocysteine Identifier CHEBI:57856 Charge 0 Formula C14H20N6O5S InChIKeyhelp_outline ZJUKTBDSGOFHSH-WFMPWKQPSA-N SMILEShelp_outline Nc1ncnc2n(cnc12)[C@@H]1O[C@H](CSCC[C@H]([NH3+])C([O-])=O)[C@@H](O)[C@H]1O 2D coordinates Mol file for the small molecule Search links Involved in 854 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline H+ Identifier CHEBI:15378 Charge 1 Formula H InChIKeyhelp_outline GPRLSGONYQIRFK-UHFFFAOYSA-N SMILEShelp_outline [H+] 2D coordinates Mol file for the small molecule Search links Involved in 9,932 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Cross-references
| RHEA:78471 | RHEA:78472 | RHEA:78473 | RHEA:78474 | |
|---|---|---|---|---|
| Reaction direction help_outline | undefined | left-to-right | right-to-left | bidirectional |
| UniProtKB help_outline |
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Publications
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Specificity and mechanism of RNA cap guanine-N2 methyltransferase (Tgs1).
Hausmann S., Shuman S.
The 2,2,7-trimethylguanosine (TMG) cap structure is characteristic of certain eukaryotic small nuclear and small nucleolar RNAs. Prior studies have suggested that cap trimethylation might be contingent on cis-acting elements in the RNA substrate, protein components of a ribonucleoprotein complex, ... >> More
The 2,2,7-trimethylguanosine (TMG) cap structure is characteristic of certain eukaryotic small nuclear and small nucleolar RNAs. Prior studies have suggested that cap trimethylation might be contingent on cis-acting elements in the RNA substrate, protein components of a ribonucleoprotein complex, or intracellular localization of the RNA substrate. However, the enzymatic requirements for TMG cap formation remain obscure because TMG synthesis has not been reconstituted in vitro from defined components. Tgs1 is a conserved eukaryal protein that was initially identified as being required for RNA cap trimethylation in vivo in budding yeast. Here we show that purified recombinant fission yeast Tgs1 catalyzes methyl transfer from S-adenosylmethionine (AdoMet) to m7GTP and m7GDP. Tgs1 also methylates the cap analog m(7)GpppA but is unreactive with GTP, GDP, GpppA, m2,2,7GTP, m2,2,7GDP, ATP, CTP, UTP, and ITP. The products of methyl transfer to m7GTP and m7GDP formed under conditions of excess methyl acceptor are 2,7-dimethyl GTP and 2,7-dimethyl GDP, respectively. Under conditions of limiting methyl acceptor, the initial m2,7GDP product is converted to m2,2,7GDP in the presence of excess AdoMet. We conclude that Tgs1 is guanine-specific, that N7 methylation must precede N2 methylation, that Tgs1 acts via a distributive mechanism, and that the chemical steps of TMG synthesis do not require input from RNA or protein cofactors. << Less
J. Biol. Chem. 280:4021-4024(2005) [PubMed] [EuropePMC]
This publication is cited by 5 other entries.
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Genetic and biochemical analysis of yeast and human cap trimethylguanosine synthase: functional overlap of 2,2,7-trimethylguanosine caps, small nuclear ribonucleoprotein components, pre-mRNA splicing factors, and RNA decay pathways.
Hausmann S., Zheng S., Costanzo M., Brost R.L., Garcin D., Boone C., Shuman S., Schwer B.
Trimethylguanosine synthase (Tgs1) is the enzyme that converts standard m(7)G caps to the 2,2,7-trimethylguanosine (TMG) caps characteristic of spliceosomal small nuclear RNAs. Fungi and mammalian somatic cells are able to grow in the absence of Tgs1 and TMG caps, suggesting that an essential func ... >> More
Trimethylguanosine synthase (Tgs1) is the enzyme that converts standard m(7)G caps to the 2,2,7-trimethylguanosine (TMG) caps characteristic of spliceosomal small nuclear RNAs. Fungi and mammalian somatic cells are able to grow in the absence of Tgs1 and TMG caps, suggesting that an essential function of the TMG cap might be obscured by functional redundancy. A systematic screen in budding yeast identified nonessential genes that, when deleted, caused synthetic growth defects with tgs1Delta. The Tgs1 interaction network embraced proteins implicated in small nuclear ribonucleoprotein function and spliceosome assembly, including Mud2, Nam8, Brr1, Lea1, Ist3, Isy1, Cwc21, and Bud13. Complementation of the synthetic lethality of mud2Delta tgs1Delta and nam8Delta tgs1Delta strains by wild-type TGS1, but not by catalytically defective mutants, indicated that the TMG cap is essential for mitotic growth when redundant splicing factors are missing. Our genetic analysis also highlighted synthetic interactions of Tgs1 with proteins implicated in RNA end processing and decay (Pat1, Lsm1, and Trf4) and regulation of polymerase II transcription (Rpn4, Spt3, Srb2, Soh1, Swr1, and Htz1). We find that the C-terminal domain of human Tgs1 can function in lieu of the yeast protein in vivo. We present a biochemical characterization of the human Tgs1 guanine-N2 methyltransferase reaction and identify individual amino acids required for methyltransferase activity in vitro and in vivo. << Less
J. Biol. Chem. 283:31706-31718(2008) [PubMed] [EuropePMC]
This publication is cited by 3 other entries.