Enzymes
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Reaction participants Show >> << Hide
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Namehelp_outline
guanosine34 in tRNA
Identifier
RHEA-COMP:10341
Reactive part
help_outline
- Name help_outline GMP residue Identifier CHEBI:74269 Charge -1 Formula C10H11N5O7P Positionhelp_outline 34 SMILEShelp_outline C1(=O)NC(=NC2=C1N=CN2[C@@H]3O[C@H](COP(=O)(*)[O-])[C@@H](O*)[C@H]3O)N 2D coordinates Mol file for the small molecule Search links Involved in 42 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline queuine Identifier CHEBI:17433 (CAS: 72496-59-4) help_outline Charge 0 Formula C12H15N5O3 InChIKeyhelp_outline WYROLENTHWJFLR-ACLDMZEESA-N SMILEShelp_outline Nc1nc2[nH]cc(CN[C@H]3C=C[C@H](O)[C@@H]3O)c2c(=O)[nH]1 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
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Namehelp_outline
queuosine34 in tRNA
Identifier
RHEA-COMP:18571
Reactive part
help_outline
- Name help_outline queuosine 5'-phosphate residue Identifier CHEBI:194431 Charge -1 Formula C17H21N5O9P Positionhelp_outline 34 SMILEShelp_outline C1(=O)NC(=NC2=C1C(=CN2[C@@H]3O[C@H](COP(*)([O-])=O)[C@@H](O*)[C@H]3O)CN[C@H]4C=C[C@@H]([C@@H]4O)O)N 2D coordinates Mol file for the small molecule Search links Involved in 6 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline guanine Identifier CHEBI:16235 (CAS: 73-40-5) help_outline Charge 0 Formula C5H5N5O InChIKeyhelp_outline UYTPUPDQBNUYGX-UHFFFAOYSA-N SMILEShelp_outline C12=C(N=C(NC1=O)N)NC=N2 2D coordinates Mol file for the small molecule Search links Involved in 16 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Cross-references
| RHEA:16633 | RHEA:16634 | RHEA:16635 | RHEA:16636 | |
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| Reaction direction help_outline | undefined | left-to-right | right-to-left | bidirectional |
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Related reactions help_outline
Specific form(s) of this reaction
Publications
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Studies with a homogeneous enzyme from rabbit erythrocytes catalyzing the insertion of guanine into tRNA.
Howes N.K., Farkas W.R.
An enzyme that catalyzes a post-transcriptional modification of tRNA, resulting in replacement of a base from tRNA by guanine, has been purified 2600-fold from rabbit erythrocyte cytosol. The purest preparation migrates as a single protein band on polycrylamide gel electrophoresis and the enzymati ... >> More
An enzyme that catalyzes a post-transcriptional modification of tRNA, resulting in replacement of a base from tRNA by guanine, has been purified 2600-fold from rabbit erythrocyte cytosol. The purest preparation migrates as a single protein band on polycrylamide gel electrophoresis and the enzymatic activity co-electrophoreses with this protein. The native enzyme has a molecular weight of 104,000 and is dissociated into two subunits of Mr= 60,000 and 43,000. The Km for guanine is 1.5 x 10(-7) M and for a pure guanine-accepting tRNA is 3.3 x 10(-9) M. The amino acid composition of the pure enzyme has been determined. To our knowledge this is the first study in which the molecular characteristics of a pure enzyme capable of modifying an internal position in tRNA has been reported. << Less
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Novel mechanism of post-transcriptional modification of tRNA. Insertion of bases of Q precursors into tRNA by a specific tRNA transglycosylase reaction.
Okada N., Noguchi S., Kasai H., Shindo-Okada N., Ohgi T., Goto T., Nishimura S.
The guanine insertion enzyme isolated from Escherichia coli (tRNA transglycosylase) catalyzed the incorporation of bases of Q (queuosine) precursors into E. coli undermodified tRNAAsn and tRNATyr. These bases of Q precursors were inserted in the first position of the anticodon of tRNASn and tRNATy ... >> More
The guanine insertion enzyme isolated from Escherichia coli (tRNA transglycosylase) catalyzed the incorporation of bases of Q (queuosine) precursors into E. coli undermodified tRNAAsn and tRNATyr. These bases of Q precursors were inserted in the first position of the anticodon of tRNASn and tRNATyr, replacing guanine originally located in that position. This is a novel type of post-transcriptional modification, inserting a modified base into the polynucleotide chain by cleavage of the N--C glycoside bond without breakage of the phosphodiester bond. One of the bases of Q precursors, 7-(aminomethyl)-7-deazaguanine, was found in the acid-soluble fraction of E. coli cells, supporting the conclusion that formation of Q, 7-(3,4-trans-4,5-cis-dihydroxy-1-cyclopenten-3-ylaminomethyl)-7-deazaguanosine, in tRNA in vivo actually proceeds by the tRNA transglycosylase reaction. << Less
J Biol Chem 254:3067-3073(1979) [PubMed] [EuropePMC]
This publication is cited by 1 other entry.
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Role of aspartate 143 in Escherichia coli tRNA-guanine transglycosylase: alteration of heterocyclic substrate specificity.
Todorov K.A., Garcia G.A.
tRNA-guanine transglycosylase (TGT) is a key enzyme involved in the post-transcriptional modification of certain tRNAs in their anticodon wobble positions with queuine. To maintain the correct Watson-Crick base pairing properties of the wobble base (and hence proper translation of the genetic code ... >> More
tRNA-guanine transglycosylase (TGT) is a key enzyme involved in the post-transcriptional modification of certain tRNAs in their anticodon wobble positions with queuine. To maintain the correct Watson-Crick base pairing properties of the wobble base (and hence proper translation of the genetic code), TGT must recognize its heterocyclic substrate with high specificity. The X-ray crystal structure of a eubacterial TGT bound to preQ1 [Romier, C., et al. (1996) EMBO J. 15, 2850-2857] suggested that aspartate 143 (Escherichia coli TGT numbering) was involved in heterocyclic substrate recognition. Subsequent mutagenic and computational modeling studies from our lab [Todorov, K. A., et al. (2005) Biophys. J. 89 (3), 1965-1977] provided experimental evidence supporting this hypothesis. Herein, we report further studies probing the differential heterocyclic substrate recognition properties of the aspartate 143 mutant TGTs. Our results are consistent with one of the mutants exhibiting an inversion of substrate recognition preference (xanthine vs guanine) relative to that of the wild type, as evidenced by Km values. This confirms the key role of aspartate 143 in maintaining the anticodon identities of the queuine-containing tRNAs and suggests that TGT mutants could be developed that would alter the tRNA wobble base base pairing properties. << Less
Biochemistry 45:617-625(2006) [PubMed] [EuropePMC]
This publication is cited by 1 other entry.