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Ribosome degradation in growing bacteria
Author(s) -
Piir Kerli,
Paier Anton,
Liiv Aivar,
Tenson Tanel,
Maiväli Ülo
Publication year - 2011
Publication title -
embo reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.584
H-Index - 184
eISSN - 1469-3178
pISSN - 1469-221X
DOI - 10.1038/embor.2011.47
Subject(s) - ribosome , ribosomal rna , exponential growth , biology , escherichia coli , microbiology and biotechnology , ribosomal protein , bacteria , bacterial growth , rna , protein biosynthesis , biochemistry , biophysics , genetics , gene , physics , quantum mechanics
Ribosomes are large ribozymes that synthesize all cellular proteins. As protein synthesis is rate‐limiting for bacterial growth and ribosomes can comprise a large portion of the cellular mass, elucidation of ribosomal turnover is important to the understanding of cellular physiology. Although ribosomes are widely believed to be stable in growing cells, this has never been rigorously tested, owing to the lack of a suitable experimental system in commonly used bacterial model organisms. Here, we develop an experimental system to directly measure ribosomal stability in Escherichia coli . We show that (i) ribosomes are stable when cells are grown at a constant rate in the exponential phase; (ii) more than half of the ribosomes made during exponential growth are degraded during slowing of culture growth preceding the entry into stationary phase; and (iii) ribosomes are stable for many hours in the stationary phase. Ribosome degradation occurs in growing cultures that contain almost no dead cells and coincides with a reduction of comparable magnitude in the cellular RNA concentration.