A giant liposome for single-molecule observation of conformational changes in membrane proteins
Artikel i vetenskaplig tidskrift, 2009

We present an experimental system that allows visualization of conformational changes in membrane proteins at the single-molecule level. The target membrane protein is reconstituted in a giant liposome for independent control of the aqueous environments on the two sides of the membrane. For direct observation of conformational changes, an extra-liposomal site(s) of the target protein is bound to a glass surface, and a probe that is easily visible under a microscope, such as a micron-sized plastic bead, is attached to another site on the intra-liposomal side. A conformational change, or an angular motion in the tiny protein molecule, would manifest as a visible motion of the probe. The attachment of the protein on the glass surface also immobilizes the liposome, greatly facilitating its manipulation such as the probe injection. As a model system, we reconstituted ATP synthase (FOF1) in liposomes tens of mu m in size, attached the protein specifically to a glass surface, and demonstrated its ATP-driven rotation in the membrane through the motion of a submicron bead. (c) 2009 Elsevier B.V. All rights reserved.


c-subunit ring


stepwise rotation

ATP synthase

Membrane protein

unilamellar vesicles


flagellar motor

kinetic mechanism

mitochondrial adenosine-triphosphatase


Giant liposome


atp synthase

resonance energy-transfer


Y. Onoue

Waseda University

The Graduate University for Advanced Studies (SOKENDAI)

T. Suzuki

Tokyo Institute of Technology

Japan Science and Technology Agency

M. Davidson


Mattias Karlsson


Owe Orwar

Chalmers, Kemi- och bioteknik, Fysikalisk kemi

M. Yoshida

Japan Science and Technology Agency

Tokyo Institute of Technology

K. Kinosita

Waseda University

Biochimica et Biophysica Acta - Biomembranes

0005-2736 (ISSN)

Vol. 1788 6 1332-1340


Fysikalisk kemi




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