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Nature. 1997 Sep 25;389(6649):403-6.

Visualization of elongation factor Tu on the Escherichia coli ribosome.

Author information

1
Imperial College of Science, Medicine and Technology, Department of Biochemistry, London, UK.

Abstract

The delivery of a specific amino acid to the translating ribosome is fundamental to protein synthesis. The binding of aminoacyl-transfer RNA to the ribosome is catalysed by the elongation factor Tu (EF-Tu). The elongation factor, the aminoacyl-tRNA and GTP form a stable 'ternary' complex that binds to the ribosome. We have used electron cryomicroscopy and angular reconstitution to visualize directly the kirromycin-stalled ternary complex in the A site of the 70S ribosome of Escherichia coli. Electron cryomicroscopy had previously given detailed ribosomal structures at 25 and 23 A resolution, and was used to determine the position of tRNAs on the ribosome. In particular, the structures of pre-translocational (tRNAs in A and P sites) and post-translocational ribosomes (P and E sites occupied) were both visualized at a resolution of approximately 20 A. Our three-dimensional reconstruction at 18 A resolution shows the ternary complex spanning the inter-subunit space with the acceptor domain of the tRNA reaching into the decoding centre. Domain 1 (the G domain) of the EF-Tu is bound both to the L7/L12 stalk and to the 50S body underneath the stalk, whereas domain 2 is oriented towards the S12 region on the 30S subunit.

PMID:
9311785
DOI:
10.1038/38770
[Indexed for MEDLINE]

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