Evidence against the double-arginine motif as the only determinant for protein translocation by a novel Sec-independent pathway in Escherichia coli.
FEMS Microbiol Lett
; 164(2): 329-36, 1998 Jul 15.
Article
in En
| MEDLINE
| ID: mdl-9682482
ABSTRACT
Proteins which are synthesized with a signal peptide containing a 'double-arginine' motif may be translocated across the bacterial cytoplasmic membrane by a mechanism that is different from the known Sec and signal recognition particle pathways. The function of the double-arginine motif as a determinant for this novel pathway was studied by expressions of gene constructs coding for the high potential iron-sulfur protein (HiPIP) from Chromatium vinosum D in Escherichia coli. When the protein was produced with its original double-arginine motif-containing signal peptide, it was in part translocated into the periplasm and thereby processed, as shown by immunoblots after cell fractionation and N-terminal sequencing of purified HiPIP. Processing was not inhibited significantly by 3 mM sodium azide, indicating that translocation of HiPIP occurs by a SecA-independent pathway. Translocation of HiPIP could be altered to the SecA-dependent mode when its signal peptide was substituted by that of PelB from Erwinia carotovora. When the HiPIP double-arginine motif (SRRDAVK) was introduced into the corresponding position of the PelB signal peptide, the transport pathway remained SecA-dependent. This indicates that additional determinants are required for translocation by the Sec-independent pathway.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Membrane Transport Proteins
/
Bacterial Proteins
/
Adenosine Triphosphatases
/
Escherichia coli Proteins
/
Photosynthetic Reaction Center Complex Proteins
/
Escherichia coli
/
Iron-Sulfur Proteins
Language:
En
Journal:
FEMS Microbiol Lett
Year:
1998
Document type:
Article
Affiliation country:
Germany