C-terminal domain of archaeal O-phosphoseryl-tRNA kinase displays large-scale motion to bind the 7-bp D-stem of archaeal tRNA(Sec).

ABSTRACT: O-Phosphoseryl-tRNA kinase (PSTK) is the key enzyme in recruiting selenocysteine (Sec) to the genetic code of archaea and eukaryotes. The enzyme phosphorylates Ser-tRNA(Sec) to produce O-phosphoseryl-tRNA(Sec) (Sep-tRNA(Sec)) that is then converted to Sec-tRNA(Sec) by Sep-tRNA:Sec-tRNA synthase. Earlier we reported the structure of the Methanocaldococcus jannaschii PSTK (MjPSTK) complexed with AMPPNP. This study presents the crystal structure (at 2.4-Å resolution) of MjPSTK complexed with an anticodon-stem/loop truncated tRNA(Sec) (Mj*tRNA(Sec)), a good enzyme substrate. Mj*tRNA(Sec) is bound between the enzyme's C-terminal domain (CTD) and N-terminal kinase domain (NTD) that are connected by a flexible 11 amino acid linker. Upon Mj*tRNA(Sec) recognition the CTD undergoes a 62-Å movement t

SUBMITTER: Sherrer RL 

PROVIDER: S-EPMC3035459 | biostudies-literature | 2011 Feb

REPOSITORIES: biostudies-literature