4v9p
From Proteopedia
Control of ribosomal subunit rotation by elongation factor G
Structural highlights
FunctionRS7_ECOLI One of the primary rRNA binding proteins, it binds directly to 16S rRNA where it nucleates assembly of the head domain of the 30S subunit. Is located at the subunit interface close to the decoding center, where it has been shown to contact mRNA. Has been shown to contact tRNA in both the P and E sites; it probably blocks exit of the E site tRNA.[1] Protein S7 is also a translational repressor protein; it regulates the expression of the str operon members to different degrees by binding to its mRNA.[2] Publication Abstract from PubMedProtein 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. Control of ribosomal subunit rotation by elongation factor G.,Pulk A, Cate JH Science. 2013 Jun 28;340(6140):1235970. doi: 10.1126/science.1235970. PMID:23812721[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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