Year of Award


Document Type


Degree Type

Doctor of Philosophy (PhD)

Other Degree Name/Area of Focus

Biochemistry, Microbiology

Department or School/College

Division of Biological Sciences

Committee Chair

J. Stephen Lodmell


Ribosomes Research., Proteins Research., Proteins Synthesis., RNA.


University of Montana


The purpose of this study was to investigate the role of ribosomal protein L ll and the LI 1-binding rRNA in translation on the prokaryotic ribosome. The L ll and LI 1-binding rRNA forms a complex on the inter-subunit face of the large ribosomal subunit, and is part of a group of ribosomal protein and rRNA elements that are separated in the secondary structure of the large subunit, but that are all linked to the functions of soluble translation factors during their interactions with ribosomes. Together the elements are referred to as the GTPase-associated region (GAR) due to their link to factor-dependent hydrolysis of guanosine triphosphate on the ribosome. Here we used structural and functional biochemical studies to specifically characterize the proximity of the LI 1/Ll 1- binding rRNA complex to other elements of the GAR, and to elucidate the role of LI 1 and the LI 1-binding rRNA in factor interactions during translation.

The evidence provided herein suggests that the LI 1/Ll 1-binding rRNA complex is proximal to other important elements of the GAR in the tertiary structure of the large subunit, and both L ll and the LI 1-binding rRNA are involved in the function of elongation factor G (EF-G) on the ribosome. Translation factor EF-G participates in elongation of a nascent peptide on the ribosome by catalyzing the translocation of transfer RNA across the ribosome as they decode messenger RNA. LI 1-binding rRNA is found to be important for binding of elongation factor G (EF-G) on the ribosome, while LI 1 is linked to EF-G-dependent GTP hydrolysis and/or turnover of EF-G during its cyclical interaction with the ribosome. The C-terminal domain of LI 1 stabilizes the structure of the LI 1-binding rRNA to allow its interaction with EF-G, while presence of the N-terminal domain of LI 1 increases the efficiency of EF-G-dependent GTP hydrolysis and/or turnover of the factor in the process of protein synthesis.



© Copyright 2004 William Sean Bowen