Membrane insertion mechanism and molecular assembly of the bacteriophage lysis toxin ΦX174-E.
FEBS J
; 288(10): 3300-3316, 2021 05.
Article
en En
| MEDLINE
| ID: mdl-33244868
ABSTRACT
The bacteriophage ΦX174 causes large pore formation in Escherichia coli and related bacteria. Lysis is mediated by the small membrane-bound toxin ΦX174-E, which is composed of a transmembrane domain and a soluble domain. The toxin requires activation by the bacterial chaperone SlyD and inhibits the cell wall precursor forming enzyme MraY. Bacterial cell wall biosynthesis is an important target for antibiotics; therefore, knowledge of molecular details in the ΦX174-E lysis pathway could help to identify new mechanisms and sites of action. In this study, cell-free expression and nanoparticle technology were combined to avoid toxic effects upon ΦX174-E synthesis, resulting in the efficient production of a functional full-length toxin and engineered derivatives. Pre-assembled nanodiscs were used to study ΦX174-E function in defined lipid environments and to analyze its membrane insertion mechanisms. The conformation of the soluble domain of ΦX174-E was identified as a central trigger for membrane insertion, as well as for the oligomeric assembly of the toxin. Stable complex formation of the soluble domain with SlyD is essential to keep nascent ΦX174-E in a conformation competent for membrane insertion. Once inserted into the membrane, ΦX174-E assembles into high-order complexes via its transmembrane domain and oligomerization depends on the presence of an essential proline residue at position 21. The data presented here support a model where an initial contact of the nascent ΦX174-E transmembrane domain with the peptidyl-prolyl isomerase domain of SlyD is essential to allow a subsequent stable interaction of SlyD with the ΦX174-E soluble domain for the generation of a membrane insertion competent toxin.
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Texto completo:
1
Base de datos:
MEDLINE
Asunto principal:
Toxinas Biológicas
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Bacteriófago phi X 174
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Isomerasa de Peptidilprolil
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Proteínas de Escherichia coli
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Escherichia coli
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Lisogenia
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Antibiosis
Idioma:
En
Revista:
FEBS J
Asunto de la revista:
BIOQUIMICA
Año:
2021
Tipo del documento:
Article