2cyc | pdb_00002cyc

Crystal structure of Tyrosyl-tRNA Synthetase complexed with L-tyrosine from Pyrococcus horikoshii

spinqualitylabelsall models 2cyc, resolution 2.20Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2cyc is a 2 chain structure with sequence from Pyrho. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: TYR Activity: Tyrosine--tRNA ligase, with EC number 6.1.1.1 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, TOPSAN Function [SYY_PYRHO] Catalyzes the attachment of tyrosine to tRNA(Tyr) in a two-step reaction: tyrosine is first activated by ATP to form Tyr-AMP and then transferred to the acceptor end of tRNA(Tyr).[HAMAP-Rule:MF_02009] 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 Tyrosyl-tRNA synthetase (TyrRS) catalyzes the tyrosylation of tRNA(Tyr) in a two-step reaction. TyrRS has the "HIGH" and "KMSKS" motifs, which play essential roles in the formation of the tyrosyl-adenylate from tyrosine and ATP. Here, we determined the crystal structures of Archaeoglobus fulgidus and Pyrococcus horikoshii TyrRSs in the l-tyrosine-bound form at 1.8A and 2.2A resolutions, respectively, and that of Aeropyrum pernix TyrRS in the substrate-free form at 2.2 A. The conformation of the KMSKS motif differs among the three TyrRSs. In the A.pernix TyrRS, the KMSKS loop conformation corresponds to the ATP-bound "closed" form. In contrast, the KMSKS loop of the P.horikoshii TyrRS forms a novel 3(10) helix, which appears to correspond to the "semi-closed" form. This conformation enlarges the entrance to the tyrosine-binding pocket, which facilitates the pyrophosphate ion release after the tyrosyl-adenylate formation, and probably is involved in the initial tRNA binding. The KMSSS loop of the A.fulgidus TyrRS is somewhat farther from the active site and is stabilized by hydrogen bonds. Based on the three structures, possible structural changes of the KMSKS motif during the tyrosine activation reaction are discussed. We suggest that the insertion sequence just before the KMSKS motif, which exists in some archaeal species, enhances the binding affinity of the TyrRS for its cognate tRNA. In addition, a non-proline cis peptide bond, which is involved in the tRNA binding, is conserved among the archaeal TyrRSs. Crystal structures of tyrosyl-tRNA synthetases from Archaea.,Kuratani M, Sakai H, Takahashi M, Yanagisawa T, Kobayashi T, Murayama K, Chen L, Liu ZJ, Wang BC, Kuroishi C, Kuramitsu S, Terada T, Bessho Y, Shirouzu M, Sekine S, Yokoyama S J Mol Biol. 2006 Jan 20;355(3):395-408. Epub 2005 Nov 14. PMID:16325203 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Aminoacyl tRNA Synthetase

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