Abstract
In Escherichia coli, components of a signal recognition particle (SRP) and its receptor have been identified which appear to be essential for efficient translocation of several proteins. In this study we use cross-linking to demonstrate that E. coli SRP interacts with a variety of nascent presecretory proteins and integral inner membrane proteins. Evidence is presented that the interaction is correlated with the hydrophobicity of the core region of the signal sequence and thereby with its ability to promote transport in vivo. A second E. coli component, which is identified as trigger factor, can be efficiently cross-linked to all tested nascent chains derived from both secreted and cytosolic proteins. We propose that SRP and trigger factor act as secretion-specific and general molecular chaperone respectively, early in protein synthesis.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Isomerases / metabolism*
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Bacterial Proteins / metabolism
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Base Sequence
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Binding Sites
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Capsid / metabolism
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Capsid Proteins*
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Carrier Proteins / metabolism*
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Cross-Linking Reagents
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DNA Primers
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Endopeptidases / metabolism
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Escherichia coli / metabolism*
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Escherichia coli Proteins*
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Membrane Proteins / metabolism
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Molecular Sequence Data
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Peptides / metabolism*
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Peptidylprolyl Isomerase
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Porins / metabolism
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Protein Precursors / metabolism
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Protein Sorting Signals / metabolism
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Serine Endopeptidases*
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Signal Recognition Particle / metabolism
Substances
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Bacterial Proteins
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Capsid Proteins
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Carrier Proteins
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Cross-Linking Reagents
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DNA Primers
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Escherichia coli Proteins
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Ffh protein, E coli
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FtsQ protein, E coli
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Membrane Proteins
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Peptides
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Porins
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Protein Precursors
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Protein Sorting Signals
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Signal Recognition Particle
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coat protein, Bacteriophage M13
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inner membrane protein, E coli
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PhoE protein, E coli
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Endopeptidases
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Serine Endopeptidases
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type I signal peptidase
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Amino Acid Isomerases
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Peptidylprolyl Isomerase