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| | <StructureSection load='1pxg' size='340' side='right'caption='[[1pxg]], [[Resolution|resolution]] 1.70Å' scene=''> | | <StructureSection load='1pxg' size='340' side='right'caption='[[1pxg]], [[Resolution|resolution]] 1.70Å' scene=''> |
| | == Structural highlights == | | == Structural highlights == |
| - | <table><tr><td colspan='2'>[[1pxg]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/"achromobacter_anaerobium"_(sic)_shimwell_1937 "achromobacter anaerobium" (sic) shimwell 1937]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1PXG OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1PXG FirstGlance]. <br> | + | <table><tr><td colspan='2'>[[1pxg]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Zymomonas_mobilis Zymomonas mobilis]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1PXG OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1PXG FirstGlance]. <br> |
| - | </td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=GOL:GLYCEROL'>GOL</scene>, <scene name='pdbligand=PRF:7-DEAZA-7-AMINOMETHYL-GUANINE'>PRF</scene>, <scene name='pdbligand=ZN:ZINC+ION'>ZN</scene></td></tr> | + | </td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 1.7Å</td></tr> |
| - | <tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">TGT ([https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=542 "Achromobacter anaerobium" (sic) Shimwell 1937])</td></tr> | + | <tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=GOL:GLYCEROL'>GOL</scene>, <scene name='pdbligand=PRF:7-DEAZA-7-AMINOMETHYL-GUANINE'>PRF</scene>, <scene name='pdbligand=ZN:ZINC+ION'>ZN</scene></td></tr> |
| - | <tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[https://en.wikipedia.org/wiki/tRNA-guanine(34)_transglycosylase tRNA-guanine(34) transglycosylase], with EC number [https://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.4.2.29 2.4.2.29] </span></td></tr>
| + | |
| | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=1pxg FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1pxg OCA], [https://pdbe.org/1pxg PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1pxg RCSB], [https://www.ebi.ac.uk/pdbsum/1pxg PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1pxg ProSAT]</span></td></tr> | | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=1pxg FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1pxg OCA], [https://pdbe.org/1pxg PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1pxg RCSB], [https://www.ebi.ac.uk/pdbsum/1pxg PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1pxg ProSAT]</span></td></tr> |
| | </table> | | </table> |
| | == Function == | | == Function == |
| - | [[https://www.uniprot.org/uniprot/TGT_ZYMMO TGT_ZYMMO]] Exchanges the guanine residue with 7-aminomethyl-7-deazaguanine in tRNAs with GU(N) anticodons (tRNA-Asp, -Asn, -His and -Tyr). After this exchange, a cyclopentendiol moiety is attached to the 7-aminomethyl group of 7-deazaguanine, resulting in the hypermodified nucleoside queuosine (Q) (7-(((4,5-cis-dihydroxy-2-cyclopenten-1-yl)amino)methyl)-7-deazaguanosine).[HAMAP-Rule:MF_00168]
| + | [https://www.uniprot.org/uniprot/TGT_ZYMMO TGT_ZYMMO] Exchanges the guanine residue with 7-aminomethyl-7-deazaguanine in tRNAs with GU(N) anticodons (tRNA-Asp, -Asn, -His and -Tyr). After this exchange, a cyclopentendiol moiety is attached to the 7-aminomethyl group of 7-deazaguanine, resulting in the hypermodified nucleoside queuosine (Q) (7-(((4,5-cis-dihydroxy-2-cyclopenten-1-yl)amino)methyl)-7-deazaguanosine).[HAMAP-Rule:MF_00168] |
| | == Evolutionary Conservation == | | == Evolutionary Conservation == |
| | [[Image:Consurf_key_small.gif|200px|right]] | | [[Image:Consurf_key_small.gif|200px|right]] |
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| | ==See Also== | | ==See Also== |
| - | *[[TRNA-guanine transglycosylase|TRNA-guanine transglycosylase]] | + | *[[TRNA-guanine transglycosylase 3D structures|TRNA-guanine transglycosylase 3D structures]] |
| | == References == | | == References == |
| | <references/> | | <references/> |
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| | </StructureSection> | | </StructureSection> |
| | [[Category: Large Structures]] | | [[Category: Large Structures]] |
| - | [[Category: Garcia, G A]] | + | [[Category: Zymomonas mobilis]] |
| - | [[Category: Kittendorf, J D]] | + | [[Category: Garcia GA]] |
| - | [[Category: Klebe, G]] | + | [[Category: Kittendorf JD]] |
| - | [[Category: Reuter, K]] | + | [[Category: Klebe G]] |
| - | [[Category: Sgraja, T]] | + | [[Category: Reuter K]] |
| - | [[Category: Tim-barrel]]
| + | [[Category: Sgraja T]] |
| - | [[Category: Transferase]]
| + | |
| Structural highlights
Function
TGT_ZYMMO Exchanges the guanine residue with 7-aminomethyl-7-deazaguanine in tRNAs with GU(N) anticodons (tRNA-Asp, -Asn, -His and -Tyr). After this exchange, a cyclopentendiol moiety is attached to the 7-aminomethyl group of 7-deazaguanine, resulting in the hypermodified nucleoside queuosine (Q) (7-(((4,5-cis-dihydroxy-2-cyclopenten-1-yl)amino)methyl)-7-deazaguanosine).[HAMAP-Rule:MF_00168]
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
tRNA-guanine transglycosylase (TGT) catalyzes a post-transcriptional base-exchange reaction involved in the incorporation of the modified base queuine (Q) into the wobble position of certain tRNAs. Catalysis by TGT occurs through a double-displacement mechanism that involves the formation of a covalent enzyme-RNA intermediate (Kittendorf, J. D., Barcomb, L. M., Nonekowski, S. T., and Garcia, G. A. (2001) Biochemistry 40, 14123-14133). The TGT chemical mechanism requires the protonation of the displaced guanine and the deprotonation of the incoming heterocyclic base. Based on its position in the active site, it is likely that aspartate 264 is involved in these proton transfer events. To investigate this possibility, site-directed mutagenesis was employed to convert aspartate 264 to alanine, asparagine, glutamate, glutamine, lysine, and histidine. Biochemical characterization of these TGT mutants revealed that only the conservative glutamate mutant retained catalytic activity, with Km values for both tRNA and guanine 3-fold greater than those for wild-type, whereas the kcat was depressed by an order of magnitude. Furthermore, of these six TGT mutants, only the TGT(D264E) was capable of forming a TGT.RNA covalent intermediate; however, unlike wild-type TGT, only hydroxylamine is capable of cleaving the TGT(D264E).RNA covalent complex. In an effort to better understand the unique biochemical properties of the D264E TGT mutant, we solved the crystal structure of the Zymomonas mobilis TGT with the analogous mutation (D280E). The results of these studies support two roles for aspartate 264 in catalysis by TGT, protonation of the leaving guanine and deprotonation of the incoming preQ1.
An essential role for aspartate 264 in catalysis by tRNA-guanine transglycosylase from Escherichia coli.,Kittendorf JD, Sgraja T, Reuter K, Klebe G, Garcia GA J Biol Chem. 2003 Oct 24;278(43):42369-76. Epub 2003 Aug 8. PMID:12909636[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Kittendorf JD, Sgraja T, Reuter K, Klebe G, Garcia GA. An essential role for aspartate 264 in catalysis by tRNA-guanine transglycosylase from Escherichia coli. J Biol Chem. 2003 Oct 24;278(43):42369-76. Epub 2003 Aug 8. PMID:12909636 doi:http://dx.doi.org/10.1074/jbc.M304323200
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