2cxi
From Proteopedia
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'''Crystal Structure Of An N-terminal Fragment Of The Phenylalanyl-tRNA Synthetase Beta-Subunit From Pyrococcus Horikoshii''' | '''Crystal Structure Of An N-terminal Fragment Of The Phenylalanyl-tRNA Synthetase Beta-Subunit From Pyrococcus Horikoshii''' | ||
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[[Category: Sekine, S.]] | [[Category: Sekine, S.]] | ||
[[Category: Yokoyama, S.]] | [[Category: Yokoyama, S.]] | ||
| - | [[Category: | + | [[Category: Aminoacyl-trna synthetase]] |
| - | [[Category: | + | [[Category: Ligase]] |
| - | [[Category: | + | [[Category: National project on protein structural and functional analyse]] |
| - | [[Category: | + | [[Category: Nppsfa]] |
| - | [[Category: | + | [[Category: Riken structural genomics/proteomics initiative]] |
| - | [[Category: | + | [[Category: Rsgi]] |
| - | [[Category: | + | [[Category: Structural genomic]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 23:17:35 2008'' | |
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Revision as of 20:17, 3 May 2008
Crystal Structure Of An N-terminal Fragment Of The Phenylalanyl-tRNA Synthetase Beta-Subunit From Pyrococcus Horikoshii
Overview
To achieve accurate aminoacylation of tRNAs with their cognate amino acids, errors in aminoacylation are corrected by the "editing" mechanism in several aminoacyl-tRNA synthetases. Phenylalanyl-tRNA synthetase (PheRS) hydrolyzes, or edits, misformed tyrosyl-tRNA with its editing domain in the beta subunit. We report the crystal structure of an N-terminal fragment of the PheRS beta subunit (PheRS-beta(N)) from the archaeon, Pyrococcus horikoshii, at 1.94-A resolution. PheRS-beta(N) includes the editing domain B3/4, which has archaea/eukarya-specific insertions/deletions and adopts a different orientation relative to other domains, as compared with that of bacterial PheRS. Surprisingly, most residues constituting the editing active-site pocket were substituted between the archaeal/eukaryal and bacterial PheRSs. We prepared Ala-substituted mutants of P. horikoshii PheRS for 16 editing-pocket residues, of which 12 are archaea/eukarya-specific and four are more widely conserved. On the basis of their activities, Tyr-adenosine was modeled on the B3/4-domain structure. First, the mutations of Leu-202, Ser-211, Asp-234, and Thr-236 made the PheRS incorrectly hydrolyze the cognate Phe-tRNA(Phe), indicating that these residues participate in the Tyr hydroxy group recognition and are responsible for discrimination against Phe. Second, the mutations of Leu-168 and Arg-223, which could interact with the tRNA 3'-terminal adenosine, reduced Tyr-tRNA(Phe) deacylation activity. Third, the mutations of archaea/eukarya-specific Gln-126, Glu-127, Arg-137, and Asn-217, which are proximal to the ester bond to be cleaved, also reduced Tyr-tRNA(Phe) deacylation activity. In particular, the replacement of Asn-217 abolished the activity, revealing its absolute requirement for the catalysis.
About this Structure
2CXI is a Single protein structure of sequence from Pyrococcus horikoshii. Full crystallographic information is available from OCA.
Reference
Structural and mutational studies of the amino acid-editing domain from archaeal/eukaryal phenylalanyl-tRNA synthetase., Sasaki HM, Sekine S, Sengoku T, Fukunaga R, Hattori M, Utsunomiya Y, Kuroishi C, Kuramitsu S, Shirouzu M, Yokoyama S, Proc Natl Acad Sci U S A. 2006 Oct 3;103(40):14744-9. Epub 2006 Sep 26. PMID:17003130 Page seeded by OCA on Sat May 3 23:17:35 2008
Categories: Phenylalanine--tRNA ligase | Pyrococcus horikoshii | Single protein | RSGI, RIKEN Structural Genomics/Proteomics Initiative. | Sasaki, H. | Sekine, S. | Yokoyama, S. | Aminoacyl-trna synthetase | Ligase | National project on protein structural and functional analyse | Nppsfa | Riken structural genomics/proteomics initiative | Rsgi | Structural genomic
