Quantitative proteomic analysis of ribosome assembly and turnover in vivo.
J Mol Biol
; 403(3): 331-45, 2010 Oct 29.
Article
em En
| MEDLINE
| ID: mdl-20709079
ABSTRACT
Although high-resolution structures of the ribosome have been solved in a series of functional states, relatively little is known about how the ribosome assembles, particularly in vivo. Here, a general method is presented for studying the dynamics of ribosome assembly and ribosomal assembly intermediates. Since significant quantities of assembly intermediates are not present under normal growth conditions, the antibiotic neomycin is used to perturb wild-type Escherichia coli. Treatment of E. coli with the antibiotic neomycin results in the accumulation of a continuum of assembly intermediates for both the 30S and 50S subunits. The protein composition and the protein stoichiometry of these intermediates were determined by quantitative mass spectrometry using purified unlabeled and (15)N-labeled wild-type ribosomes as external standards. The intermediates throughout the continuum are heterogeneous and are largely depleted of late-binding proteins. Pulse-labeling with (15)N-labeled medium time-stamps the ribosomal proteins based on their time of synthesis. The assembly intermediates contain both newly synthesized proteins and proteins that originated in previously synthesized intact subunits. This observation requires either a significant amount of ribosome degradation or the exchange or reuse of ribosomal proteins. These specific methods can be applied to any system where ribosomal assembly intermediates accumulate, including strains with deletions or mutations of assembly factors. This general approach can be applied to study the dynamics of assembly and turnover of other macromolecular complexes that can be isolated from cells.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Proteínas Ribossômicas
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Ribossomos
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RNA Ribossômico
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Proteoma
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Proteínas de Escherichia coli
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Escherichia coli
Tipo de estudo:
Guideline
Idioma:
En
Revista:
J Mol Biol
Ano de publicação:
2010
Tipo de documento:
Article
País de afiliação:
Estados Unidos