3p0h

Leishmania major Tyrosyl-tRNA synthetase in complex with fisetin, cubic crystal form

spinqualitylabelsall models 3p0h, resolution 3.00Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3p0h is a 2 chain structure with sequence from Leishmania major. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 3Å Ligands: FSE, MSE Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function Q4QFJ7_LEIMA Publication Abstract from PubMed The single tyrosyl tRNA synthetase (TyrRS) gene in trypanosomatid genomes codes for a protein that is twice the length of TyrRS from virtually all other organisms. Each half of the double-length TyrRS contains a catalytic domain and an anticodon-binding domain; however, the two halves retain only 17% sequence identity to each other. The structural and functional consequences of this duplication and divergence are unclear. TyrRS normally forms a homodimer in which the active site of one monomer pairs with the anticodon-binding domain from the other. However, crystal structures of Leishmania major TyrRS show that, instead, the two halves of a single molecule form a pseudo-dimer resembling the canonical TyrRS dimer. Curiously, the C-terminal copy of the catalytic domain has lost the catalytically important HIGH and KMSKS motifs characteristic of class I aminoacyl tRNA synthetases. Thus, the pseudo-dimer contains only one functional active site (contributed by the N-terminal half) and only one functional anticodon recognition site (contributed by the C-terminal half). Despite biochemical evidence for negative cooperativity between the two active sites of the usual TyrRS homodimer, previous structures have captured a crystallographically imposed symmetric state. As the L. major TyrRS pseudo-dimer is inherently asymmetric, conformational variations observed near the active site may be relevant to understanding how the state of a single active site is communicated across the dimer interface. Furthermore, substantial differences between trypanosomal TyrRS and human homologs are promising for the design of inhibitors that selectively target the parasite enzyme. The Double-Length Tyrosyl tRNA Synthetase from the Eukaryote Leishmania major Forms an Intrinsically Asymmetric Pseudo-Dimer.,Larson ET, Kim JE, Castaneda LJ, Napuli AJ, Zhang Z, Fan E, Zucker FH, Verlinde CL, Buckner FS, Van Voorhis WC, Hol WG, Merritt EA J Mol Biol. 2011 Mar 21. PMID:21420975 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Aminoacyl tRNA synthetase 3D structures

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