Probing the energy landscape of the membrane protein bacteriorhodopsin
Publikation: Beitrag in Fachzeitschrift › Forschungsartikel › Beigetragen › Begutachtung
Beitragende
Abstract
The folding and stability of transmembrane proteins is a fundamental and unsolved biological problem. Here, single bacteriorhodopsin molecules were mechanically unfolded from native purple membranes using atomic force microscopy and force spectroscopy. The energy landscape of individual transmembrane α helices and polypeptide loops was mapped by monitoring the pulling speed dependence of the unfolding forces and applying Monte Carlo simulations. Single helices formed independently stable units stabilized by a single potential barrier. Mechanical unfolding of the helices was triggered by 3.9-7.7 Å extension, while natural unfolding rates were of the order of 10-3 s-1. Besides acting as individually stable units, helices associated pairwise, establishing a collective potential barrier. The unfolding pathways of individual proteins reflect distinct pulling speed-dependent unfolding routes in their energy landscapes. These observations support the two-stage model of membrane protein folding in which α helices insert into the membrane as stable units and then assemble into the functional protein.
Details
Originalsprache | Englisch |
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Seiten (von - bis) | 871-879 |
Seitenumfang | 9 |
Fachzeitschrift | Structure |
Jahrgang | 12 |
Ausgabenummer | 5 |
Publikationsstatus | Veröffentlicht - Mai 2004 |
Peer-Review-Status | Ja |
Extern publiziert | Ja |
Externe IDs
PubMed | 15130479 |
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