1vq7
From Proteopedia
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| , resolution 2.5Å | |||||||
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| Ligands: | , , , and | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
The structure of the transition state analogue "DCA" bound to the large ribosomal subunit of haloarcula marismortui
Overview
The large ribosomal subunit catalyses the reaction between the alpha-amino group of the aminoacyl-tRNA bound to the A site and the ester carbon of the peptidyl-tRNA bound to the P site, while preventing the nucleophilic attack of water on the ester, which would lead to unprogrammed deacylation of the peptidyl-tRNA. Here we describe three new structures of the large ribosomal subunit of Haloarcula marismortui (Hma) complexed with peptidyl transferase substrate analogues that reveal an induced-fit mechanism in which substrates and active-site residues reposition to allow the peptidyl transferase reaction. Proper binding of an aminoacyl-tRNA analogue to the A site induces specific movements of 23S rRNA nucleotides 2618-2620 (Escherichia coli numbering 2583-2585) and 2541(2506), thereby reorienting the ester group of the peptidyl-tRNA and making it accessible for attack. In the absence of the appropriate A-site substrate, the peptidyl transferase centre positions the ester link of the peptidyl-tRNA in a conformation that precludes the catalysed nucleophilic attack by water. Protein release factors may also function, in part, by inducing an active-site rearrangement similar to that produced by the A-site aminoacyl-tRNA, allowing the carbonyl group and water to be positioned for hydrolysis.
About this Structure
1VQ7 is a Protein complex structure of sequences from Haloarcula marismortui. Full crystallographic information is available from OCA.
Reference
An induced-fit mechanism to promote peptide bond formation and exclude hydrolysis of peptidyl-tRNA., Schmeing TM, Huang KS, Strobel SA, Steitz TA, Nature. 2005 Nov 24;438(7067):520-4. PMID:16306996
Page seeded by OCA on Thu Mar 20 14:48:17 2008
