The crystal structure of leucyl-tRNA synthetase complexed with tRNALeu in the post-transfer-editing conformation.
Leucyl-tRNA synthetase (LeuRS) has a specific post-transfer editing activity directed against mischarged isoleucine and similar noncognate amino acids. We describe the post-transfer-editing and product complexes of Thermus thermophilus LeuRS (LeuRSTT) with tRNA(Leu) at 2.9- to 3.3-A resolution. In the post-transfer-editing configuration, A76 binds in the editing active site exactly as previously found for the adenosine moiety of a small-molecule editing-substrate analog. The 60 C-terminal residues of LeuRSTT, unseen in previous structures, fold into a compact domain flexibly linked to the rest of the molecule and interacting with the G19-C56 tertiary base pair of tRNA(Leu). LeuRS recognition of tRNA(Leu) depends essentially on tRNA shape rather than base-specific interactions. The structures show that considerable domain rotations, notably of the editing domain, accompany the tRNA-3' end dynamics associated successively with aminoacylation, post-transfer editing and product release.
Tukalo
Michael
M
European Molecular Biology Laboratory, Grenoble Outstation, c/o Institut Laue-Langevin, 156X, F-38042 Grenoble Cedex 9, France.
Yaremchuk
Anna
A
Fukunaga
Ryuya
R
Yokoyama
Shigeyuki
S
Cusack
Stephen
S
D000595:Amino Acid Sequence; D001483:Base Sequence; D018360:Crystallography, X-Ray; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D011487:Protein Conformation; D017393:RNA Editing; D012346:RNA, Transfer, Amino Acyl / Q000737:chemistry*; D012356:RNA, Transfer, Leu / Q000737:chemistry*; D016963:Thermus thermophilus / Q000201:enzymology* / Q000235:genetics*; D046249:Transfer RNA Aminoacylation
D012346:RNA, Transfer, Amino Acyl; D012356:RNA, Transfer, Leu