Translocation of a functional protein by a voltage-dependent ion channel.
The voltage-dependent gating of the colicin channel involves a substantial structural rearrangement that results in the transfer of about 35% of the 200 residues in its pore-forming domain across the membrane. This transfer appears to represent an unusual type of protein translocation that does not depend on a large, multimeric, protein pore. To investigate the ability of this system to transport arbitrary proteins, we made use of a pair of strongly interacting proteins, either of which could serve as a translocated cargo or as a probe to detect the other. Here we show that both an 86-residue and a 134-residue hydrophilic protein inserted into the translocated segment of colicin A are themselves translocated and are functional on the trans side of the bilayer. The disparate features of these proteins suggest that the colicin channel has a general protein translocation mechanism.
Slatin
Stephen L
SL
Albert Einstein College of Medicine, Bronx, NY 10461, USA. slatin@aecom.yu.edu
Nardi
Angèle
A
Jakes
Karen S
KS
Baty
Daniel
D
Duché
Denis
D
D000595:Amino Acid Sequence; D001665:Binding Sites; D003062:Codon; D003087:Colicins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D003851:Deoxyribonucleases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D015640:Ion Channel Gating; D008051:Lipid Bilayers; D008954:Models, Biological; D008969:Molecular Sequence Data; D011487:Protein Conformation; D055503:Protein Multimerization; D021381:Protein Transport
D003062:Codon; D003087:Colicins; D008051:Lipid Bilayers; D003851:Deoxyribonucleases