ISSN:
1574-6968
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Biology
Notes:
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.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1574-6968.1998.tb13106.x
