PMID: 23812721 , Related PDB ids: 4KIX, 4KIY, 4KIZ, 4KJ0, 4KJ1, 4KJ2, 4KJ3, 4KJ4, 4KJ5, 4KJ6, 4KJ7, 4KJ8, 4KJ9, 4KJA, 4KJB, 4KJC

Authors:

Pulk A, Cate JH

Title:

Control of ribosomal subunit rotation by elongation factor G.

Journal:

Science. 2013 Jun 28;340(6140):1235970. doi: 10.1126/science.1235970.

Abstract:

Protein synthesis by the ribosome requires the translocation of transfer RNAs and messenger RNA by one codon after each peptide bond is formed, a reaction that requires ribosomal subunit rotation and is catalyzed by the guanosine triphosphatase (GTPase) elongation factor G (EF-G). We determined 3 angstrom resolution x-ray crystal structures of EF-G complexed with a nonhydrolyzable guanosine 5'-triphosphate (GTP) analog and bound to the Escherichia coli ribosome in different states of ribosomal subunit rotation. The structures reveal that EF-G binding to the ribosome stabilizes switch regions in the GTPase active site, resulting in a compact EF-G conformation that favors an intermediate state of ribosomal subunit rotation. These structures suggest that EF-G controls the translocation reaction by cycles of conformational rigidity and relaxation before and after GTP hydrolysis.