2quh
From Proteopedia
Crystal structures of human tryptophanyl-tRNA synthetase in complex with Trp
Structural highlights
Function[SYWC_HUMAN] Isoform 1, isoform 2 and T1-TrpRS have aminoacylation activity while T2-TrpRS lacks it. Isoform 2, T1-TrpRS and T2-TrpRS possess angiostatic activity whereas isoform 1 lacks it. T2-TrpRS inhibits fluid shear stress-activated responses of endothelial cells. Regulates ERK, Akt, and eNOS activation pathways that are associated with angiogenesis, cytoskeletal reorganization and shear stress-responsive gene expression.[1] [2] [3] [4] 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 PubMedHuman tryptophanyl-tRNA synthetase (hTrpRS) differs from its bacterial counterpart at several key positions of the catalytic active site and has an extra N-terminal domain, implying possibly a different catalytic mechanism. We report here the crystal structures of hTrpRS in complexes with Trp, tryptophanamide and ATP and tryptophanyl-AMP, respectively, which represent three different enzymatic states of the Trp activation reaction. Analyses of these structures reveal the molecular basis of the mechanisms of the substrate recognition and the activation reaction. The dimeric hTrpRS is structurally and functionally asymmetric with half-of-the-sites reactivity. Recognition of Trp is by an induced-fit mechanism involving conformational change of the AIDQ motif that creates a perfect pocket for the binding and activation of Trp and causes coupled movements of the N-terminal and C-terminal domains. The KMSAS loop appears to have an inherent flexibility and the binding of ATP stabilizes it in a closed conformation that secures the position of ATP for catalysis. Our structural data indicate that the catalytic mechanism of the Trp activation reaction by hTrpRS involves more moderate conformational changes of the structural elements at the active site to recognize and bind the substrates, which is more complex and fine-tuned than that of bacterial TrpRS. Catalytic mechanism of the tryptophan activation reaction revealed by crystal structures of human tryptophanyl-tRNA synthetase in different enzymatic states.,Shen N, Zhou M, Yang B, Yu Y, Dong X, Ding J Nucleic Acids Res. 2008 Mar;36(4):1288-99. Epub 2008 Jan 7. PMID:18180246[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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