SecY-mediated quality control prevents the translocation of non-gated porins.
Sci Rep
; 10(1): 16347, 2020 10 01.
Article
in En
| MEDLINE
| ID: mdl-33004891
ABSTRACT
OmpC and OmpF are among the most abundant outer membrane proteins in E. coli and serve as hydrophilic channels to mediate uptake of small molecules including antibiotics. Influx selectivity is controlled by the so-called constriction zone or eyelet of the channel. Mutations in the loop domain forming the eyelet can disrupt transport selectivity and thereby interfere with bacterial viability. In this study we show that a highly conserved motif of five negatively charged amino acids in the eyelet, which is critical to regulate pore selectivity, is also required for SecY-mediated transport of OmpC and OmpF into the periplasm. Variants with a deleted or mutated motif were expressed in the cytosol and translocation was initiated. However, after signal peptide cleavage, import into the periplasm was aborted and the mutated proteins were redirected to the cytosol. Strikingly, reducing the proof-reading capacity of SecY by introducing the PrlA4 substitutions restored transport of OmpC with a mutated channel domain into the periplasm. Our study identified a SecY-mediated quality control pathway to restrict transport of outer membrane porin proteins with a deregulated channel activity into the periplasm.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Porins
/
Periplasm
/
Escherichia coli Proteins
/
Escherichia coli
/
SEC Translocation Channels
Language:
En
Journal:
Sci Rep
Year:
2020
Document type:
Article
Affiliation country: