Sandbox Reserved 704: Difference between revisions
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Aminoacyl-tRNA synthetases (aaRSs) are ligases which exclusively attach a particular amino acid to the 3’ of its set of cognate tRNAs isoacceptors. It is a two-step reaction: First, an activated intermediate called aminoacyladenylate is synthesized from the amino acid and ATP. Then, the activated amino acid is transferred to the 3’-end of the tRNA. It leads to the formation of the aminoacyl-tRNA. The fidelity of protein synthesis depends of the accuracy of this reaction <ref name="Zhou">PMID:20482517</ref>. | Aminoacyl-tRNA synthetases (aaRSs) are ligases which exclusively attach a particular amino acid to the 3’ of its set of cognate tRNAs isoacceptors. It is a two-step reaction: First, an activated intermediate called aminoacyladenylate is synthesized from the amino acid and ATP. Then, the activated amino acid is transferred to the 3’-end of the tRNA. It leads to the formation of the aminoacyl-tRNA. The fidelity of protein synthesis depends of the accuracy of this reaction <ref name="Zhou">PMID:20482517</ref>. | ||
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== Identity elements involved in complex formation == | == Identity elements involved in complex formation == | ||
<StructureSection load='1wz2' size='300' frame='true' align='left' side='right' caption='(PDB entry [[1wz2]])' scene=''/> | |||
Most aaRSs interact with the tRNA anticodon loop in order to form aminoacyl-tRNA complex. But in the case of archaeal LeuRSs, none of them use this recognition mode. In fact, LeuRSs use two identity elements: the discriminator A73 and the long variable arm. | Most aaRSs interact with the tRNA anticodon loop in order to form aminoacyl-tRNA complex. But in the case of archaeal LeuRSs, none of them use this recognition mode. In fact, LeuRSs use two identity elements: the discriminator A73 and the long variable arm. | ||
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== Structural differences between the two complexes == | == Structural differences between the two complexes == | ||
The first complex is observed when the CCA end localized at the 3' end of tRNA Leu is located in the aminoacylation active site; it is the aminoacylation complex. | The first complex is observed when the CCA end localized at the 3' end of tRNA Leu is located in the aminoacylation active site; it is the aminoacylation complex. | ||
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| A73 and C74 are perpendicular to each other | | A73 and C74 are perpendicular to each other | ||
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!scope="col" | !scope="col" Recognitions mode A73 | ||
|Hydrogen bond between N1 of A73 and NH of Asp504 in the main chain | |Hydrogen bond between N1 of A73 and NH of Asp504 in the main chain | ||
| Hydrogen bond between N6-H2 of A73 and CO of Lys 505 in the main chain | | Hydrogen bond between N6-H2 of A73 and CO of Lys 505 in the main chain | ||
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{| class="wikitable centre" | {| class="wikitable centre" | ||
| The editing complex | !scope="col" | The editing complex | ||
!scope="col" | The aminoacylation complex | |||
|- | |- | ||
| The phosphate group between C74 and C75 interacts with the arg510 side chain || The phosphate group between C74 and C75 interacts with the arg510 side chain | | The phosphate group between C74 and C75 interacts with the arg510 side chain || The phosphate group between C74 and C75 interacts with the arg510 side chain | ||
|- | |- | ||
| The phosphate group between C75 and A76 interacts with the ser85 and ser528 side chains | The phosphate group between C75 and A76 do not interact with serine residues | | The phosphate group between C75 and A76 interacts with the ser85 and ser528 side chains | ||
| The phosphate group between C75 and A76 do not interact with serine residues | |||
|- | |- | ||
|Hydrogen bond between N6-H2 of A76 and Asn616 in the side chain || Hydrogen bond between N7 of A76 and Asn616 in the side chain | |Hydrogen bond between N6-H2 of A76 and Asn616 in the side chain || Hydrogen bond between N7 of A76 and Asn616 in the side chain | ||
