title: Crystal structures of Entamoeba histolytica lysyl-tRNA synthetase reveal conformational changes upon lysine binding and a specific helix bundle domain.
abstract: The class II lysyl-tRNA synthetases (KRS) are conserved aminoacyl-tRNA synthetases that attach lysine to the cognate tRNA in a two-step mechanism. The enzyme from the parasitic protozoan Entamoeba histolytica was crystallized in the presence of small ligands to generate snapshots of the lysine-adenylate formation. The residues involved in lysine activation are highly conserved and the active site closes around the lysyl-adenylate, as observed in bacterial KRS. The Entamoeba EMAPII-like polypeptide is not resolved in the crystals, but another Entamoeba-specific insertion could be modeled as a small helix bundle that may contribute to tRNA binding through interaction with the tRNA hinge.
authors.affiliation: Department of Biophysics and Biochemistry, Graduate School of Science, The University of Tokyo, 2-11-16, Yayoi, Bunkyo, Tokyo 113-0032, Japan. lbonnefond@unistra.fr
authors.forename: Luc
authors.initials: L
authors.lastname: Bonnefond
authors.forename: Manuel
authors.initials: M
authors.lastname: Castro de Moura
authors.forename: Lluis
authors.initials: L
authors.lastname: Ribas de Pouplana
authors.forename: Osamu
authors.initials: O
authors.lastname: Nureki
mesh_terms: D000595:Amino Acid Sequence; D001051:Apoenzymes / Q000737:chemistry / Q000378:metabolism; D020134:Catalytic Domain / Q000187:drug effects; D018360:Crystallography, X-Ray; D004748:Entamoeba histolytica / Q000201:enzymology*; D008239:Lysine / Q000378:metabolism* / Q000494:pharmacology*; D008250:Lysine-tRNA Ligase / Q000737:chemistry* / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011485:Protein Binding; D017433:Protein Structure, Secondary / Q000187:drug effects; D012343:RNA, Transfer / Q000378:metabolism
chemical_list: D001051:Apoenzymes; D012343:RNA, Transfer; D008250:Lysine-tRNA Ligase; D008239:Lysine