Free-energy landscapes of membrane co-translocational protein unfolding
Protein post-translational translocation is found at the plasma membrane of prokaryotes and protein import into organellae. Translocon structures are becoming available, however the dynamics of proteins during membrane translocation remain largely obscure. Here we study, at the single-molecule level...
| Autores: | , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2020 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/337950 |
| Acceso en línea: | http://hdl.handle.net/10261/337950 https://api.elsevier.com/content/abstract/scopus_id/85083041831 |
| Access Level: | acceso abierto |
| Palabra clave: | Molecular biophysics Single-molecule biophysics |
| Sumario: | Protein post-translational translocation is found at the plasma membrane of prokaryotes and protein import into organellae. Translocon structures are becoming available, however the dynamics of proteins during membrane translocation remain largely obscure. Here we study, at the single-molecule level, the folding landscape of a model protein while forced to translocate a transmembrane pore. We use a DNA tag to drive the protein into the α-hemolysin pore under a quantifiable force produced by an applied electric potential. Using a voltage-quench approach we find that the protein fluctuates between the native state and an intermediate in the translocation process at estimated forces as low as 1.9 pN. The fluctuation kinetics provide the free energy landscape as a function of force. We show that our stable, ≈15 kBT, substrate can be unfolded and translocated with physiological membrane potentials and that selective divalent cation binding may have a profound effect on the translocation kinetics. |
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