The pore-forming colicin E1 shares the property of all the E colicins in using the vitamin B12 transporter BtuB as its primary receptor in the outer membrane. Mol Gen Genet. ;(1) Cloning of colicin E1 tolerant tolC (mtcB) gene of Escherichia coli K12 and identification of its gene product. Otsuji N, Soejima. The mechanism of export of colicins E1 and E3 was examined. Neither colicin E1 , colicin E3, Nor colicin E3 immunity protein appears to be synthesized as a.

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Further study is required to confirm this. For the first step in killing target bacteria, the colicins have evolved to cannibalize as their primary high-affinity cell surface receptors one of a small number of outer membrane proteins FhuA, FepA, BtuB, and Cir normally used by the target bacteria for the uptake of essential nutrients, such as siderophore-bound iron or cobalamin.

Mechanism of export of colicin E1 and colicin E3.

Summary of colicin E1 T domain peptide protection of E. Such resistant cells may suffer the lack of a key nutrient such as iron or a B vitaminbut benefit by not being killed. The percentage of surviving coliciin was calculated from the control culture to which no colicin or T domain was added.

Once the colicin is bound at the cell surface, however, it must still cross the membrane on which it is bound. Deletion of either the receptor-binding domain of the colicin or of the bacteria’s BtuB receptor reduces cytotoxicity by three or four orders of magnitude, but it does not totally prevent killing colicinn the colicin. Error bars represent the range from three independent experiments. The mechanism of export of colicins E1 and E3 was examined.


I thank Alan Finkelstein for many helpful discussions and for critically reading the manuscript. The problem remains, however, as to how even an extended polypeptide chain could exit the narrow s1.

For colicin Ee1, a pore-forming colicin, a second copy of its Cir receptor serves as its translocator 10 Colicin spot tests, killing assays in liquid culture, and protection assays with T domain. All of MyBioSource’s Products are for scientific laboratory research purposes and are not for diagnostic, therapeutics, prophylactic or in vivo use. Journal List J Bacteriol v.

TolC, colicins, drug efflux, membrane translocation, toxins. Substrate-induced assembly of a contiguous channel for protein export from E. It is this translocation step of colicin E1 intoxication that is the subject of this study. Assembly and channel opening in a bacterial drug efflux machine. The colicim structure of the TolB box of colicin A in complex with TolB reveals important differences in the recruitment of the common TolB translocation portal used by group A colicins.

A colicin is a type of bacteriocin produced by and toxic to some strains of Escherichia coli.

Colicin E1 (microcin) immunity protein (IPR) < InterPro < EMBL-EBI

Increasingly shorter T domain peptides were then constructed and tested for their ability to block killing by the colicin. For long-term storage, store at degrees C or degrees C.

Salmonella Infection Pathway antibodies. Subsequent recently published biophysical measurements using this same set of peptides showed that this sequence is also required for the in vitro binding of the T domain to TolC, as measured by either occlusion of TolC channels in planar lipid bilayer membranes or binding to a size exclusion column The structure shows this channel forming domain of ColE1. Similarly, T1—, which did not protect, was included as a negative control.

However, in each pair that was made, regardless of its N terminus, the peptides ending in residue protected cells from cytotoxicity by colicin E1, as did the peptides ending in residue The second is involved with translocation, co-opting the machinery of the target cell.


Mechanism of export of colicin E1 and colicin E3.

Structure-function of the channel-forming colicins. It is the responsibility of the customer to report product performance issues to MyBioSource within 30 days of receipt of the product. Your Inquiries or Comments. They could detect in vivo cross-linking of E1 to TolC by dithiobis succinimidyl propionate DSP in cells with a functional BtuB colicin receptor but not in btuB mutant cells. Regardless of their ultimate killing mechanism, all colicins must cross at least the outer membrane in order to reach their targets.

These studies were initiated after encouragement from and extensive conversations with William A. Focal Adhesion Pathway antibodies. Channel-forming colicins colicins A, B, E1, Ia, Ib, and N are transmembrane proteins that depolarize the cytoplasmic membrane, leading to dissipation of cellular energy.

The receptor-binding R domain, encompassing amino acid residues towas deleted from the colicin E1 gene in pKSJ, which has the genes for colicin E1 and ImmE1 cloned in pUC19 44using the QuikChange site-directed mutagenesis kit Agilent Technologies.

The colicin’s R domain binds to Cir with high affinity, allowing for a more efficient search, while anchored at the cell surface, by its T domain for another nearby copy of Cir, through which it transits s1 the periplasm by an as-yet poorly understood mechanism that must involve some movement of the plug domain of Cir. The third is the ‘killing’ domain and may produce a pore in the target w1 membraneor act as a nuclease to chop up the DNA or RNA of the target cell.