Two complementary enzymes for threonylation of tRNA in crenarchaeota: crystal structure of Aeropyrum pernix threonyl-tRNA synthetase lacking a cis-editing domain
| Autor: | K. Suzuki, Ella Czarina Magat Juan, Y. Miyashita, Takeshi Sekiguchi, Masaru Tsunoda, Tsubasa Sagara, Dino Moras, Anne-Catherine Dock-Bregeon, Yoshiteru Sato, Satoru Shimizu, Md. Mominul Hoque, Akio Takénaka |
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| Rok vydání: | 2009 |
| Předmět: |
Threonine
Protein Folding Molecular Sequence Data Aminoacylation RNA Archaeal RNA Transfer Amino Acyl Crystallography X-Ray chemistry.chemical_compound Structural Biology Protein biosynthesis Threonine-tRNA Ligase Aeropyrum pernix Amino Acid Sequence Molecular Biology chemistry.chemical_classification DNA ligase biology Aminoacyl tRNA synthetase Aeropyrum biology.organism_classification Amino acid Protein Structure Tertiary chemistry Biochemistry Transfer RNA Transfer RNA Aminoacylation Pyrococcus abyssi |
| Zdroj: | Journal of molecular biology. 394(2) |
| ISSN: | 1089-8638 |
| Popis: | In protein synthesis, threonyl-tRNA synthetase (ThrRS) must recognize threonine (Thr) from the 20 kinds of amino acids and the cognate tRNA Thr from different tRNAs in order to generate Thr-tRNA Thr . In general, an organism possesses one kind of gene corresponding to ThrRS. However, it has been recently found that some organisms have two different genes for ThrRS in the genome, suggesting that their proteins ThrRS-1 and ThrRS-2 function separately and complement each other in the threonylation of tRNA Thr , one for catalysis and the other for trans-editing of misacylated Ser-tRNA Thr . In order to clarify their three-dimensional structures, we performed X-ray analyses of two putatively assigned ThrRSs from Aeropyrum pernix ( Ap ThrRS-1 and Ap ThrRS-2). These proteins were overexpressed in Escherichia coli , purified, and crystallized. The crystal structure of Ap ThrRS-1 has been successfully determined at 2.3 A resolution. Ap ThrRS-1 is a dimeric enzyme composed of two identical subunits, each containing two domains for the catalytic reaction and for anticodon binding. The essential editing domain is completely missing as expected. These structural features reveal that ThrRS-1 catalyzes only the aminoacylation of the cognate tRNA, suggesting the necessity of the second enzyme ThrRS-2 for trans-editing. Since the N-terminal sequence of Ap ThrRS-2 is similar to the sequence of the editing domain of ThrRS from Pyrococcus abyssi , Ap ThrRS-2 has been expected to catalyze deaminoacylation of a misacylated serine moiety at the CCA terminus. |
| Databáze: | OpenAIRE |
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