Putative membrane assembly of EtpM-colicin V chimeras.
EtpM of the enterohemorrhagic E. coli O157:H7 is a bitopic membrane protein of the type II protein secretion apparatus. There is a twin-arginine (RR) motif in front of its signal anchor, suggesting a Tat-dependent membrane targeting of EtpM. By exploiting the periplasmic bactericidal activity of colicin V (ColV), we constructed EtpM-ColV fusions and studied the EtpM-mediated translocation of ColV. The wild type strain and the DeltatatC mutant were killed by the expressed fusions and were fully protected from the killing effect by the ColV-specific immunity protein. In contrast, cold-inactivation of YidC, which is generally required for integral membrane protein assembly, significantly attenuated the killing effect in the cold-sensitive yidC mutant. These results confirmed the predicted N(in)-C(out) EtpM topology, and suggests an EtpM-mediated, Tat-independent and YidC-dependent translocation of ColV.
Gérard
Fabien
F
Laboratoire de Chimie Bactérienne, UPR9043, Institut de Biologie Structurale et Microbiologie, CNRS, 31, chemin Joseph Aiguier 13402Marseille cedex 20, France.
Pradel
Nathalie
N
Ye
Changyun
C
Ize
Bérengère
B
Yi
Liang
L
Xu
Jianguo
J
Dalbey
Ross E
RE
Wu
Long-Fei
LF
D020816:Amino Acid Motifs; D001120:Arginine; D002462:Cell Membrane / Q000378:metabolism*; D003080:Cold Temperature; D003087:Colicins / Q000235:genetics / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism; D019453:Escherichia coli O157 / Q000166:cytology / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D015696:Gene Products, tat / Q000235:genetics / Q000378:metabolism; D007425:Intracellular Membranes / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D009154:Mutation / Q000235:genetics; D019897:Periplasm / Q000378:metabolism; D010641:Phenotype; D017510:Protein Folding; D021381:Protein Transport; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D013697:Thermosensing
D003087:Colicins; D029968:Escherichia coli Proteins; D015696:Gene Products, tat; D026901:Membrane Transport Proteins; D011993:Recombinant Fusion Proteins; D001120:Arginine