1qvf

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spinqualitylabelsall models 1qvf, resolution 3.1Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

Structure of a deacylated tRNA minihelix bound to the E site of the large ribosomal subunit of Haloarcula marismortui

Overview

During translation, tRNAs cycle through three binding sites on the, ribosome: the A, the P, and the E sites. We have determined the structures, of complexes between the Haloarcula marismortui large ribosomal subunit, and two different E site substrates: a deacylated tRNA acceptor stem, minihelix and a CCA-acceptor end. Both of these tRNA mimics contain, analogs of adenosine 76, the component responsible for a large proportion, of E site binding affinity. They bind in the center of the loop-extension, of protein L44e, and make specific contacts with both L44e and 23S rRNA, including bases that are conserved in all three kingdoms of life. These, contacts are consistent with the footprinting, protection, and, cross-linking data that have identified the E site biochemically. These, structures explain the specificity of the E site for deacylated tRNAs, as, it is too small to accommodate any relevant aminoacyl-tRNA. The, orientation of the minihelix suggests that it may mimic the P/E hybrid, state. It appears that the E site on the 50S subunit was formed by only, RNA in the last common ancestor of the three kingdoms, since the proteins, at the E sites of H. marismortui and Deinucoccus radiodurans large, subunits are not homologous.

About this Structure

1QVF is a Protein complex structure of sequences from Haloarcula marismortui with MG, K, NA, CD and CL as ligands. Full crystallographic information is available from OCA.

Reference

Structures of deacylated tRNA mimics bound to the E site of the large ribosomal subunit., Schmeing TM, Moore PB, Steitz TA, RNA. 2003 Nov;9(11):1345-52. PMID:14561884

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