title: Crystal structure of the aspartyl-tRNA synthetase from Entamoeba histolytica.
abstract: The crystal structure of the aspartyl-tRNA synthetase from the eukaryotic parasite Entamoeba histolytica has been determined at 2.8Aresolution. Relative to homologous sequences, the E. histolytica protein contains a 43-residue insertion between the N-terminal anticodon binding domain and the C-terminal catalytic domain. The present structure reveals that this insertion extends an arm of the hinge region that has previously been shown to mediate interaction of aspartyl-tRNA synthetase with the cognate tRNA D-stem. Modeling indicates that this Entamoeba-specific insertion is likely to increase the interaction surface with the cognate tRNA(Asp). In doing so it may substitute functionally for an RNA-binding motif located in N-terminal extensions found in AspRS sequences from lower eukaryotes but absent in Entamoeba. The E. histolytica AspRS structure shows a well-ordered N-terminus that contributes to the AspRS dimer interface.
authors.affiliation: Department of Biochemistry, University of Washington, Mailstop 357742, Seattle, WA 98195, USA. merritt@u.washington.edu
authors.forename: Ethan A
authors.initials: EA
authors.lastname: Merritt
authors.forename: Tracy L
authors.initials: TL
authors.lastname: Arakaki
authors.forename: Eric T
authors.initials: ET
authors.lastname: Larson
authors.forename: Angela
authors.initials: A
authors.lastname: Kelley
authors.forename: Natascha
authors.initials: N
authors.lastname: Mueller
authors.forename: Alberto J
authors.initials: AJ
authors.lastname: Napuli
authors.forename: Li
authors.initials: L
authors.lastname: Zhang
authors.forename: George
authors.initials: G
authors.lastname: Deditta
authors.forename: Joseph
authors.initials: J
authors.lastname: Luft
authors.forename: Christophe L M J
authors.initials: CL
authors.lastname: Verlinde
authors.forename: Erkang
authors.initials: E
authors.lastname: Fan
authors.forename: Frank
authors.initials: F
authors.lastname: Zucker
authors.forename: Frederick S
authors.initials: FS
authors.lastname: Buckner
authors.forename: Wesley C
authors.initials: WC
authors.lastname: Van Voorhis
authors.forename: Wim G J
authors.initials: WG
authors.lastname: Hol
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001226:Aspartate-tRNA Ligase / Q000737:chemistry* / Q000235:genetics; D018360:Crystallography, X-Ray; D004748:Entamoeba histolytica / Q000737:chemistry* / Q000201:enzymology*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary; D015800:Protozoan Proteins / Q000737:chemistry*; D016415:Sequence Alignment
chemical_list: D015800:Protozoan Proteins; D001226:Aspartate-tRNA Ligase