Authors

A. Naganathan;S. D. Moore

Comments

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Abbreviated Journal Title

J. Bacteriol.

Keywords

ESCHERICHIA-COLI RIBOSOMES; BACILLUS-SUBTILIS; BACTERIAL RIBOSOME; NUCLEOTIDE-BINDING; MESSENGER-RNA; DOMAINS; SUBUNIT; 50S; BACTERIOPHAGE-T4; SWITCH; Microbiology

Abstract

Ribosomal protein L9 is a component of all eubacterial ribosomes, yet deletion strains display only subtle growth defects. Although L9 has been implicated in helping ribosomes maintain translation reading frame and in regulating translation bypass, no portion of the ribosome-bound protein seems capable of contacting either the peptidyltransferase center or the decoding center, so it is a mystery how L9 can influence these important processes. To reveal the physiological roles of L9 that have maintained it in evolution, we identified mutants of Escherichia coli that depend on L9 for fitness. In this report, we describe a class of L9-dependent mutants in the ribosome biogenesis GTPase Der (EngA/YphC). Purified mutant proteins were severely compromised in their GTPase activities, despite the fact that the mutations are not present in GTP hydrolysis sites. Moreover, although L9 and YihI complemented the slow-growth der phenotypes, neither factor could rescue the GTPase activities in vitro. Complementation studies revealed that the N-terminal domain of L9 is necessary and sufficient to improve the fitness of these Der mutants, suggesting that this domain may help stabilize compromised ribosomes that accumulate when Der is defective. Finally, we employed a targeted degradation system to rapidly deplete L9 from a highly compromised der mutant strain and show that the L9-dependent phenotype coincides with a cell division defect.

Journal Title

Journal of Bacteriology

Volume

195

Issue/Number

16

Publication Date

1-1-2013

Document Type

Article

Language

English

First Page

3682

Last Page

3691

WOS Identifier

WOS:000322226100020

ISSN

0021-9193

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