Enzymes
UniProtKB help_outline | 44,394 proteins |
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Reaction participants Show >> << Hide
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Namehelp_outline
adenosine37 in tRNA
Identifier
RHEA-COMP:10162
Reactive part
help_outline
- Name help_outline AMP residue Identifier CHEBI:74411 Charge -1 Formula C10H11N5O6P Positionhelp_outline 37 SMILEShelp_outline NC1=NC=NC2=C1N=CN2[C@@H]3O[C@H](COP(=O)(*)[O-])[C@@H](O*)[C@H]3O 2D coordinates Mol file for the small molecule Search links Involved in 40 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline dimethylallyl diphosphate Identifier CHEBI:57623 (Beilstein: 5288443; CAS: 22679-02-3) help_outline Charge -3 Formula C5H9O7P2 InChIKeyhelp_outline CBIDRCWHNCKSTO-UHFFFAOYSA-K SMILEShelp_outline CC(C)=CCOP([O-])(=O)OP([O-])([O-])=O 2D coordinates Mol file for the small molecule Search links Involved in 79 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline diphosphate Identifier CHEBI:33019 (Beilstein: 185088) help_outline Charge -3 Formula HO7P2 InChIKeyhelp_outline XPPKVPWEQAFLFU-UHFFFAOYSA-K SMILEShelp_outline OP([O-])(=O)OP([O-])([O-])=O 2D coordinates Mol file for the small molecule Search links Involved in 1,129 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
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Namehelp_outline
N6-dimethylallyladenosine37 in tRNA
Identifier
RHEA-COMP:10375
Reactive part
help_outline
- Name help_outline N6-(3-methylbut-2-en-1-yl)-adenosine 5'-phosphate residue Identifier CHEBI:74415 Charge -1 Formula C15H19N5O6P Positionhelp_outline 37 SMILEShelp_outline N(C1=NC=NC2=C1N=CN2[C@@H]3O[C@H](COP(=O)(*)[O-])[C@@H](O*)[C@H]3O)CC=C(C)C 2D coordinates Mol file for the small molecule Search links Involved in 3 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Cross-references
RHEA:26482 | RHEA:26483 | RHEA:26484 | RHEA:26485 | |
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Reaction direction help_outline | undefined | left-to-right | right-to-left | bidirectional |
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Publications
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Escherichia coli dimethylallyl diphosphate:tRNA dimethylallyltransferase: pre-steady-state kinetic studies.
Moore J.A., Mathis J.R., Poulter C.D.
Escherichia coli dimethylallyl diphosphate:tRNA dimethylallyltransferase (DMAPP-tRNA transferase) catalyzes the first step in the biosynthesis of the hypermodified A37 residue in tRNAs that read codons beginning with uridine. The mechanism of the enzyme-catalyzed reaction was studied by isotope tr ... >> More
Escherichia coli dimethylallyl diphosphate:tRNA dimethylallyltransferase (DMAPP-tRNA transferase) catalyzes the first step in the biosynthesis of the hypermodified A37 residue in tRNAs that read codons beginning with uridine. The mechanism of the enzyme-catalyzed reaction was studied by isotope trapping, pre-steady-state rapid quench, and single turnover experiments. Isotope trapping indicated that the enzyme.tRNA complex is catalytically competent, whereas the enzyme.DMAPP complex is not. The results are consistent with an ordered sequential mechanism for substrate binding where tRNA binds first. The association and dissociation rate constants for the enzyme.tRNA binary complex are 1. 15+/-0.33x10(7) M(-1) s(-1) and 0.06+/-0.01 s(-1), respectively. Addition of DMAPP gives an enzyme.tRNA.DMAPP ternary complex in rapid equilibrium with the binary complex and DMAPP. Rapid quench studies yielded a linear profile (k(cat)=0.36+/-0.01 s(-1)) with no evidence for buildup of enzyme-bound product. Product release from DMAPP-tRNA transferase is therefore not rate-limiting. The Michaelis constant for tRNA and the equilibrium dissociation constant for DMAPP calculated from the individual rate constants determined here are consistent with values obtained from a steady-state kinetic analysis. << Less
Biochim Biophys Acta 1479:166-174(2000) [PubMed] [EuropePMC]
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Escherichia coli dimethylallyl diphosphate:tRNA dimethylallyltransferase: essential elements for recognition of tRNA substrates within the anticodon stem-loop.
Soderberg T., Poulter C.D.
Escherichia coli dimethylallyl diphosphate:tRNA dimethylallyltransferase (DMAPP-tRNA transferase) catalyzes the alkylation of the exocyclic amine of A37 by a dimethylallyl unit in tRNAs with an adenosine in the third anticodon position (position 36). By use of purified recombinant enzyme, steady-s ... >> More
Escherichia coli dimethylallyl diphosphate:tRNA dimethylallyltransferase (DMAPP-tRNA transferase) catalyzes the alkylation of the exocyclic amine of A37 by a dimethylallyl unit in tRNAs with an adenosine in the third anticodon position (position 36). By use of purified recombinant enzyme, steady-state kinetic studies were conducted with chemically synthesized RNA oligoribonucleotides to determine the essential elements within the tRNA anticodon stem-loop structure required for recognition by the enzyme. A 17-base oligoribonucleotide corresponding to the anticodon stem-loop of E. coli tRNA(Phe) formed a stem-loop minihelix (minihelix(Phe)) when annealed rapidly on ice, while the same molecule formed a duplex structure with a central loop when annealed slowly at higher concentrations. Both the minihelix and duplex structures gave k(cat)s similar to that for the normal substrate (full-length tRNA(Phe) unmodified at A37), although the K(m) for minihelix(Phe) was approximately 180-fold higher than full-length tRNA. The A36-A37-A38 motif, which is completely conserved in tRNAs modified by the enzyme, was found to be important for modification. Changing A36 to G in the minihelix resulted in a 260-fold reduction in k(cat) compared to minihelix(Phe) and a 13-fold increase in K(m). An A38G variant was modified with a 9-fold reduction in k(cat) and a 5-fold increase in K(m). A random coil 17-base oligoribonucleotide in which the loop sequence of E. coli tRNA(Phe) was preserved, but the 5 base pair helix stem was completely disrupted and showed no measurable activity, indicating that a helix-loop structure is essential for recognition. Finally, altering the identity of several base pairs in the helical stem did not have a major effect on catalytic efficiency, suggesting that the enzyme does not make base-specific contacts important for binding or catalysis in this region. << Less