1QRT image
Deposition Date 1996-06-14
Release Date 1996-12-07
Last Version Date 2024-10-16
Entry Detail
PDB ID:
1QRT
Keywords:
Title:
GLUTAMINYL-TRNA SYNTHETASE MUTANT D235G COMPLEXED WITH GLUTAMINE TRANSFER RNA
Biological Source:
Source Organism:
Escherichia coli (Taxon ID: 562)
Host Organism:
Method Details:
Experimental Method:
Resolution:
2.70 Å
R-Value Work:
0.21
R-Value Observed:
0.21
Space Group:
C 2 2 21
Macromolecular Entities
Polymer Type:polypeptide(L)
Molecule:PROTEIN (GLUTAMINYL-TRNA SYNTHETASE (E.C.6.1.1.18))
Gene (Uniprot):glnS
Mutations:D235G
Chain IDs:B (auth: A)
Chain Length:553
Number of Molecules:1
Biological Source:Escherichia coli
Polymer Type:polyribonucleotide
Molecule:TRNAGLN2
Chain IDs:A (auth: B)
Chain Length:75
Number of Molecules:1
Biological Source:Escherichia coli
Ligand Molecules
Primary Citation
Crystal structures of three misacylating mutants of Escherichia coli glutaminyl-tRNA synthetase complexed with tRNA(Gln) and ATP.
Biochemistry 35 14725 14733 (1996)
PMID: 8942633 DOI: 10.1021/bi961532o

Abstact

Three previously described mutant Escherichia coli glutaminyl-tRNA synthetase (GlnRS) proteins that incorrectly aminoacylate the amber suppressor derived from tRNATyr (supF) with glutamine were cocrystallized with wild-type tRNAGln and their structures determined. In two of the mutant enzymes studied, Asp235, which contacts base pair G3-C70 in the acceptor stem, has been changed to asparagine in GlnRS7 and to glycine in GlnRS10. These mutations result in changed interactions between Asn235 of GlnRS7 and G3-C70 of the tRNA and an altered water structure between Gly235 of GlnRS10 and base pair G3-C70. These structures suggest how the mutant enzymes can show only small changes in their ability to aminoacylate wild-type cognate tRNA on the one hand and yet show a lack of discrimination against a noncognate U3-A70 base pair on the other. In contrast, the change of Ile129 to Thr in GlnRS15 causes virtually no change in the structure of the complex, and the explanation for its ability to misacylate supF is unclear.

Legend

Protein

Chemical

Disease

Primary Citation of related structures