Localization of L11 protein on the ribosome and elucidation of its involvement in EF-G-dependent translocation

• Published in: Journal of molecular biology 2001-08, Vol.311 (4), p.777-787
• Main Authors: Agrawal, Rajendra K, Linde, Jamie, Sengupta, Jayati, Nierhaus, Knud H, Frank, Joachim
• Format: Article
• Language: English
• Subjects: Cryoelectron Microscopy; Crystallography, X-Ray; elongation factor EF-G; elongation factor release; Escherichia coli; Escherichia coli - chemistry; Escherichia coli - genetics; Escherichia coli Proteins; Gene Deletion; Guanosine Triphosphate - metabolism; Hydrolysis; Models, Molecular; Peptide Elongation Factor G - metabolism; Protein Binding; Protein Structure, Quaternary; Protein Structure, Tertiary; Protein Subunits; ribosomal protein L11; Ribosomal Proteins - chemistry; Ribosomal Proteins - genetics; Ribosomal Proteins - metabolism; Ribosomal Proteins - ultrastructure; ribosomal subunit 50S; Ribosomes - chemistry; Ribosomes - metabolism; Ribosomes - ultrastructure; thiostrepton; translation
• ISSN: 0022-2836; 1089-8638
• DOI: 10.1006/jmbi.2001.4907

L11 protein is located at the base of the L7/L12 stalk of the 50 S subunit of the Escherichia coli ribosome. Because of the flexible nature of the region, recent X-ray crystallographic studies of the 50 S subunit failed to locate the N-terminal domain of the protein. We have determined the position of the complete L11 protein by comparing a three-dimensional cryo-EM reconstruction of the 70 S ribosome, isolated from a mutant lacking ribosomal protein L11, with the three-dimensional map of the wild-type ribosome. Fitting of the X-ray coordinates of L11-23 S RNA complex and EF-G into the cryo-EM maps combined with molecular modeling, reveals that, following EF-G-dependent GTP hydrolysis, domain V of EF-G intrudes into the cleft between the 23 S ribosomal RNA and the N-terminal domain of L11 (where the antibiotic thiostrepton binds), causing the N-terminal domain to move and thereby inducing the formation of the arc-like connection with the G′ domain of EF-G. The results provide a new insight into the mechanism of EF-G-dependent translocation.