Recognition of the 70S ribosome and polysome by the RNA degradosome in Escherichia coli.
Nucleic Acids Res
; 40(20): 10417-31, 2012 Nov 01.
Article
en En
| MEDLINE
| ID: mdl-22923520
ABSTRACT
The RNA degradosome is a multi-enzyme assembly that contributes to key processes of RNA metabolism, and it engages numerous partners in serving its varied functional roles. Small domains within the assembly recognize collectively a diverse range of macromolecules, including the core protein components, the cytoplasmic lipid membrane, mRNAs, non-coding regulatory RNAs and precursors of structured RNAs. We present evidence that the degradosome can form a stable complex with the 70S ribosome and polysomes, and we demonstrate the proximity in vivo of ribosomal proteins and the scaffold of the degradosome, RNase E. The principal interactions are mapped to two, independent, RNA-binding domains from RNase E. RhlB, the RNA helicase component of the degradosome, also contributes to ribosome binding, and this is favoured through an activating interaction with RNase E. The catalytic activity of RNase E for processing 9S RNA (the ribosomal 5S RNA precursor) is repressed in the presence of the ribosome, whereas there is little affect on the cleavage of single-stranded substrates mediated by non-coding RNA, suggestings that the enzyme retains capacity to cleave unstructured substrates when associated with the ribosome. We propose that polysomes may act as antennae that enhance the rates of capture of the limited number of degradosomes, so that they become recruited to sites of active translation to act on mRNAs as they become exposed or tagged for degradation.
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Polirribonucleótido Nucleotidiltransferasa
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Polirribosomas
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Ribosomas
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ARN Helicasas
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Endorribonucleasas
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Escherichia coli
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Complejos Multienzimáticos
Idioma:
En
Revista:
Nucleic Acids Res
Año:
2012
Tipo del documento:
Article
País de afiliación:
Reino Unido