Summary information and primary citation
- PDB-id
-
1qtq;
DSSR-derived features in text and
JSON formats
- Class
- ligase-RNA
- Method
- X-ray (2.25 Å)
- Summary
- Glutaminyl-trna synthetase complexed with trna and an
amino acid analog
- Reference
-
Rath VL, Silvian LF, Beijer B, Sproat BS, Steitz TA
(1998): "How
glutaminyl-tRNA synthetase selects glutamine."
Structure, 6, 439-449. doi:
10.1016/S0969-2126(98)00046-X.
- Abstract
- Background: Aminoacyl-tRNA synthetases covalently link
a specific amino acid to the correct tRNA. The fidelity of
this reaction is essential for accurate protein synthesis.
Each synthetase has a specific molecular mechanism to
distinguish the correct pair of substrates from the pool of
amino acids and isologous tRNA molecules. In the case of
glutaminyl-tRNA synthetase (GlnRS) the prior binding of
tRNA is required for activation of glutamine by ATP. A
complete understanding of amino acid specificity in GlnRS
requires the determination of the structure of the
synthetase with both tRNA and substrates bound.
Results: A stable glutaminly-adenylate analog, which
inhibits GlnRS with a Ki of 1.32 microM, was synthesized
and cocrystallized with GlnRS and tRNA2Gln. The crystal
structure of this ternary complex has been refined at 2.4 A
resolution and shows the interactions made between
glutamine and its binding site.
Conclusions: To select against glutamic acid or glutamate,
both hydrogen atoms of the nitrogen of the glutamine
sidechain are recognized. The hydroxyl group of Tyr211 and
a water molecule are responsible for this recognition; both
are obligate hydrogen-bond acceptors due to a network of
interacting sidechains and water molecules. The prior
binding of tRNAGln that is required for amino acid
activation may result from the terminal nucleotide, A76,
packing against and orienting Tyr211, which forms part of
the amino acid binding site.
