| Autor: |
Serdiuk, T, Sugihara, J, Mari, SA, Kaback, HR, Müller, DJ |
| Jazyk: |
angličtina |
| Rok vydání: |
2015 |
| Předmět: |
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| Zdroj: |
Serdiuk, T; Sugihara, J; Mari, SA; Kaback, HR; Kaback, HR; Kaback, HR; et al.(2015). Observing a Lipid-Dependent Alteration in Single Lactose Permeases. Structure. doi: 10.1016/j.str.2015.02.009. UCLA: Retrieved from: http://www.escholarship.org/uc/item/4tq954wf |
| Popis: |
© 2015 Elsevier Ltd. Lipids of the . Escherichia coli membrane are mainly composed of 70%-80% phosphatidylethanolamine (PE) and 20%-25% phosphatidylglycerol (PG). Biochemical studies indicate that the depletion of PE causes inversion of the N-terminal helix bundle of the lactose permease (LacY), and helix VII becomes extramembranous. Here we study this phenomenon using single-molecule force spectroscopy, which is sensitive to the structure of membrane proteins. In PE and PG at a ratio of 3:1, ~95% of the LacY molecules adopt a native structure. However, when PE is omitted and the membrane contains PG only, LacY almost equally populates a native and a perturbed conformation. The most drastic changes occur at helices VI and VII and the intervening loop. Since helix VII contains Asp237 and Asp240, zwitterionic PE may suppress electrostatic repulsion between LacY and PG in the PE:PG environment. Thus, PE promotes a native fold and prevents LacY from populating a functionally defective, nonnative conformation. Serdiuk etal. structurally localize the interactions that stabilize single lactose permeases (LacY) in phospholipid membranes. In the absence of phosphatidylethanolamine, LacY adopts perturbed conformations, thus suggesting an alternating topology. Drastic changes are located at helices VI and VII and the intervening loop. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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