title: Crystal structure of tRNA pseudouridine synthase TruA from Thermus thermophilus HB8.
abstract: The pseudouridine synthase (Psi synthase) TruA catalyzes the conversion of uridine to pseudouridine at positions 38, 39 and/or 40 in the anticodon stem-loop (ASL) of tRNA. We have determined the crystal structure of TruA from Thermus thermophilus HB8 at 2.25 A resolution. TruA and the other (Psi synthases have a completely conserved active site aspartate, which suggests that the members of this enzyme family share a common catalytic mechanism. The T. thermophilus TruA structure reveals the remarkably flexible structural features in the tRNA-binding cleft, which may be responsible for the primary tRNA interaction. In addition, the charged residues occupying the intermediate positions in the cleft may lead the tRNA to the active site for catalysis. Based on the TruB-tRNA complex structure, the T. thermophilus TruA structure reveals that the tRNA probably makes the melting base pairs move into the cleft, and suggests that a conformational change of the substrate tRNA is necessary to facilitate access to the active site aspartate residue, deep within the cleft.
authors.affiliation: RIKEN Genomic Sciences Center, Tsurumi, Yokohama, Japan.
authors.forename: Xuesong
authors.initials: X
authors.lastname: Dong
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Bessho
authors.forename: Rie
authors.initials: R
authors.lastname: Shibata
authors.forename: Madoka
authors.initials: M
authors.lastname: Nishimoto
authors.forename: Mikako
authors.initials: M
authors.lastname: Shirouzu
authors.forename: Seiki
authors.initials: S
authors.lastname: Kuramitsu
authors.forename: Shigeyuki
authors.initials: S
authors.lastname: Yokoyama
mesh_terms: D012313:RNA / Q000235:genetics*
chemical_list: D012313:RNA