2re8 | pdb_00002re8

Glutaminyl-tRNA synthetase mutant C229R with bound analog 5'-O-[N-(L-GLUTAMYL)-SULFAMOYL]ADENOSINE

spinqualitylabelsall models 2re8, resolution 2.60Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2re8 is a 2 chain structure with sequence from "bacillus_coli"_migula_1895 "bacillus coli" migula 1895. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: GSU, SO4 Related: 2rd2 Gene: glnS ("Bacillus coli" Migula 1895) Activity: Glutamine--tRNA ligase, with EC number 6.1.1.18 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed Information transfer from nucleic acid to protein is mediated by aminoacyl-tRNA synthetases, which catalyze the specific pairings of amino acids with transfer RNAs. Despite copious sequence and structural information on the 22 tRNA synthetase families, little is known of the enzyme signatures that specify amino acid selectivities. Here, we show that transplanting a conserved arginine residue from glutamyl-tRNA synthetase (GluRS) to glutaminyl-tRNA synthetase (GlnRS) improves the K(M) of GlnRS for noncognate glutamate. Two crystal structures of this C229R GlnRS mutant reveal that a conserved twin-arginine GluRS amino acid identity signature cannot be incorporated into GlnRS without disrupting surrounding protein structural elements that interact with the tRNA. Consistent with these findings, we show that cumulative replacement of other primary binding site residues in GlnRS, with those of GluRS, only slightly improves the ability of the GlnRS active site to accommodate glutamate. However, introduction of 22 amino acid replacements and one deletion, including substitution of the entire primary binding site and two surface loops adjacent to the region disrupted in C229R, improves the capacity of Escherichia coli GlnRS to synthesize misacylated Glu-tRNA(Gln) by 16,000-fold. This hybrid enzyme recapitulates the function of misacylating GluRS enzymes found in organisms that synthesize Gln-tRNA(Gln) by an alternative pathway. These findings implicate the RNA component of the contemporary GlnRS-tRNA(Gln) complex in mediating amino acid specificity. This role for tRNA may persist as a relic of primordial cells in which the evolution of the genetic code was driven by RNA-catalyzed amino acid-RNA pairing. A rationally engineered misacylating aminoacyl-tRNA synthetase.,Bullock TL, Rodriguez-Hernandez A, Corigliano EM, Perona JJ Proc Natl Acad Sci U S A. 2008 May 27;105(21):7428-33. Epub 2008 May 13. PMID:18477696 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Aminoacyl tRNA Synthetase

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