1EXD

CRYSTAL STRUCTURE OF A TIGHT-BINDING GLUTAMINE TRNA BOUND TO GLUTAMINE AMINOACYL TRNA SYNTHETASE

Summary for 1EXD

• Entry DOI: 10.2210/pdb1exd/pdb
• Related: 1QTQ
• Descriptor: GLUTAMINE TRNA APTAMER, GLUTAMINYL-TRNA SYNTHETASE, SULFATE ION, ... (5 entities in total)
• Functional Keywords: engineered trna, trna-protein complex, trna aptamer, ligase-rna complex, ligase/rna
• Biological source: Escherichia coli; More
• Cellular location: Cytoplasm: P00962
• Total number of polymer chains: 2
• Total formula weight: 87057.48

Authors

Bullock, T.L.,Sherlin, L.D.,Perona, J.J. (deposition date: 2000-05-02, release date: 2000-05-15, Last modification date: 2024-05-29)

Primary citation

Bullock, T.L.,Sherlin, L.D.,Perona, J.J.
Tertiary core rearrangements in a tight binding transfer RNA aptamer.
Nat.Struct.Biol., 7:497-504, 2000

PubMed Abstract: Guided by an in vitro selection experiment designed to obtain tight binding aptamers of Escherichia coli glutamine specific tRNA (tRNAGln) for glutaminyl-tRNA synthetase (GlnRS), we have engineered a tRNA mutant in which the five-nucleotide variable loop sequence 5'-44CAUUC48-3' is replaced by 5'-44AGGU48-3'. This mutant tRNA binds to GlnRS with 30-fold improved affinity compared to the wild type. The 2.7 A cocrystal structure of the RNA aptamer-GlnRS complex reveals major rearrangements in the central tertiary core of the tRNA, while maintaining an RNA-protein interface identical to the wild type. The repacked RNA core features a novel hydrogen bonding arrangement of the trans Levitt pair G15-U48, a new sulfate binding pocket in the major groove, and increased hydrophobic stacking interactions among the bases. These data suggest that enhanced protein binding to a mutant globular RNA can arise from stabilization of RNA tertiary interactions rather than optimization of RNA-protein contacts.

PubMed: 10881199
DOI: 10.1038/75910

Experimental method

X-RAY DIFFRACTION (2.7 Å)