Electric-Field-Induced Protein Translocation via a Conformational Transition in SecDF: An MD Study
| Autor: | Ioan Andricioaei, Emel Ficici, Daun Jeong |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
0301 basic medicine
Conformational change Protein Conformation Static Electricity Biophysics Molecular Dynamics Simulation 010402 general chemistry 01 natural sciences Reaction coordinate 03 medical and health sciences Molecular dynamics Electromagnetic Fields Bacterial Proteins Chemiosmosis Chemistry Membrane Transport Proteins Proteins Biological Sciences Translocon Transmembrane protein 0104 chemical sciences Dipole Crystallography 030104 developmental biology Physical Sciences Chemical Sciences Umbrella sampling Protons |
| Zdroj: | Biophysical journal, vol 112, iss 12 |
| ISSN: | 1542-0086 |
| Popis: | SecDF is an important component of the Sec protein translocation machinery embedded in the bacterial membrane, which is associated with many functions, such as stabilizing other Sec translocon components within the membrane, maintaining the transmembrane (TM) potential, and facilitating the ATP-independent stage of the translocation mechanism. Related studies suggest that SecDF undergoes functionally important conformational changes that involve mainly its P1-head domain and that these changes are coupled with the proton motive force (Δp). However, there still is not a clear understanding of how SecDF functions, its exact role in the translocation machinery, and how its function is related to Δp. Here, using all-atom molecular dynamics simulations combined with umbrella sampling, we study the P1-head conformational change and how it is coupled to the proton motive force. We report potentials of mean force along a root-mean-square-distance-based reaction coordinate obtained in the presence and absence of the TM electrical potential. Our results show that the interaction of the P1 domain dipole moment with the TM electrical field considerably lowers the free-energy barrier in the direction of F-form to I-form transition. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|