AppppA-binding protein E89 is the Escherichia coli heat shock protein ClpB.
J Bacteriol
; 175(8): 2321-6, 1993 Apr.
Article
em En
| MEDLINE
| ID: mdl-8468292
ABSTRACT
Dinucleotide AppppA (5',5'''-P1,P4-diadenosine tetraphosphate) is rapidly synthesized in Escherichia coli cells during heat shock. apaH mutants lack AppppN hydrolase activity and, therefore, contain constitutively levels of AppppA, which affect several cellular processes. However, the precise role of AppppA remains undetermined. Photo-crosslinking experiments with radioactively labelled azido-AppppA have shown that a number of proteins, including heat shock proteins DnaK and GroEL, specifically bind to AppppA. Several other unidentified proteins (C40, C45, and E89) also bind strongly to AppppA. In this work, we have identified the AppppA-binding protein E89 as heat shock protein ClpB. In addition, since ClpB belongs to a family of proteins implicated in proteolysis, we have examined the effects of apaH mutants on protein degradation. Constitutively elevated levels of AppppA stimulate lon-independent proteolysis only in heat-shocked cells. We also show that overproduction of ClpB from a plasmid rescues apaH mutants from sensitivity to killing by heat.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Fosfatos de Dinucleosídeos
/
Proteínas de Transporte
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Proteínas de Escherichia coli
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Escherichia coli
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Proteínas de Choque Térmico
Idioma:
En
Revista:
J Bacteriol
Ano de publicação:
1993
Tipo de documento:
Article
País de publicação:
EEUU
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ESTADOS UNIDOS
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ESTADOS UNIDOS DA AMERICA
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EUA
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UNITED STATES
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UNITED STATES OF AMERICA
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US
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USA