The extended loops of ribosomal proteins uL4 and uL22 of Escherichia coli contribute to ribosome assembly and protein translation

Author/Creator ORCID

Date

2016-06-01

Department

Program

Citation of Original Publication

Marlon G. Lawrence, et.al, The extended loops of ribosomal proteins uL4 and uL22 of Escherichia coli contribute to ribosome assembly and protein translation, Nucleic Acids Res. 2016 Jul 8; 44(12): 5798–5810, 2016 , DOI: 10.1093/nar/gkw493

Rights

This item is likely protected under Title 17 of the U.S. Copyright Law. Unless on a Creative Commons license, for uses protected by Copyright Law, contact the copyright holder or the author.
This article has been accepted for publication in Nucleic Acids Research Published by Oxford University Press.

Abstract

Nearly half of ribosomal proteins are composed of a domain on the ribosome surface and a loop or extension that penetrates into the organelle's RNA core. Our previous work showed that ribosomes lacking the loops of ribosomal proteins uL4 or uL22 are still capable of entering polysomes. However, in those experiments we could not address the formation of mutant ribosomes, because we used strains that also expressed wild-type uL4 and uL22. Here, we have focused on ribosome assembly and function in strains in which loop deletion mutant genes are the only sources of uL4 or uL22 protein. The uL4 and uL22 loop deletions have different effects, but both mutations result in accumulation of immature particles that do not accumulate in detectable amounts in wild-type strains. Thus, our results suggest that deleting the loops creates kinetic barriers in the normal assembly pathway, possibly resulting in assembly via alternate pathway(s). Furthermore, deletion of the uL4 loop results in cold-sensitive ribosome assembly and function. Finally, ribosomes carrying either of the loop-deleted proteins responded normally to the secM translation pausing peptide, but the uL4 mutant responded very inefficiently to the cmlAᶜʳᵇ pause peptide.