Directional Porin Binding of Intrinsically Disordered Protein Sequences Promotes Colicin Epitope Display in the Bacterial Periplasm.
Biochemistry
; 57(29): 4374-4381, 2018 07 24.
Article
en En
| MEDLINE
| ID: mdl-29949342
Protein bacteriocins are potent narrow spectrum antibiotics that exploit outer membrane porins to kill bacteria by poorly understood mechanisms. Here, we determine how colicins, bacteriocins specific for Escherichia coli, engage the trimeric porin OmpF to initiate toxin entry. The N-terminal â¼80 residues of the nuclease colicin ColE9 are intrinsically unstructured and house two OmpF binding sites (OBS1 and OBS2) that reside within the pores of OmpF and which flank an epitope that binds periplasmic TolB. Using a combination of molecular dynamics simulations, chemical trimerization, isothermal titration calorimetry, fluorescence microscopy, and single channel recording planar lipid bilayer measurements, we show that this arrangement is achieved by OBS2 binding from the extracellular face of OmpF, while the interaction of OBS1 occurs from the periplasmic face of OmpF. Our study shows how the narrow pores of oligomeric porins are exploited by colicin disordered regions for direction-specific binding, which ensures the constrained presentation of an activating signal within the bacterial periplasm.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Porinas
/
Colicinas
/
Escherichia coli
/
Proteínas Intrínsecamente Desordenadas
Idioma:
En
Revista:
Biochemistry
Año:
2018
Tipo del documento:
Article
Pais de publicación:
Estados Unidos