Abstract
The mechanism by which a signal recognition particle (SRP) and its receptor mediate protein targeting to the endoplasmic reticulum or to the bacterial plasma membrane is evolutionarily conserved. In Escherichia coli, this reaction is mediated by the Ffh/4.5S RNA ribonucleoprotein complex (Ffh/4.5S RNP; the SRP) and the FtsY protein (the SRP receptor). We have quantified the effects of 4.5S RNA on Ffh-FtsY complex formation by monitoring changes in tryptophan fluorescence. Surprisingly, 4.5S RNA facilitates both assembly and disassembly of the Ffh-FtsY complex to a similar extent. These results provide an example of an RNA molecule facilitating protein-protein interactions in a catalytic fashion.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Bacterial Proteins / chemistry
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Bacterial Proteins / metabolism*
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Catalysis
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Escherichia coli / metabolism
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Escherichia coli Proteins*
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Guanosine Diphosphate / metabolism
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Guanosine Triphosphate / metabolism
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Guanylyl Imidodiphosphate / metabolism
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Kinetics
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Models, Chemical
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Nucleic Acid Conformation
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Protein Binding
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Protein Conformation
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Protein Structure, Tertiary
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RNA, Bacterial / chemistry
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RNA, Bacterial / metabolism*
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Receptors, Cytoplasmic and Nuclear / chemistry
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Receptors, Cytoplasmic and Nuclear / metabolism*
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Ribonucleoproteins / chemistry
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Ribonucleoproteins / metabolism
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Signal Recognition Particle / chemistry
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Signal Recognition Particle / metabolism*
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Spectrometry, Fluorescence
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Thermodynamics
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Tryptophan
Substances
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Bacterial Proteins
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Escherichia coli Proteins
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Ffh protein, E coli
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FtsY protein, Bacteria
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RNA, Bacterial
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Receptors, Cytoplasmic and Nuclear
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Ribonucleoproteins
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Signal Recognition Particle
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Guanosine Diphosphate
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Guanylyl Imidodiphosphate
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Guanosine Triphosphate
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Tryptophan