TY - JOUR
T1 - A giant liposome for single-molecule observation of conformational changes in membrane proteins
AU - Onoue, Yasuhiro
AU - Suzuki, Toshiharu
AU - Davidson, Max
AU - Karlsson, Mattias
AU - Orwar, Owe
AU - Yoshida, Masasuke
AU - Kinosita, Kazuhiko
PY - 2009/6
Y1 - 2009/6
N2 - 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 μm 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.
AB - 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 μm 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.
KW - ATP synthase
KW - Conformational change
KW - Giant liposome
KW - Membrane protein
KW - Single-molecule
UR - http://www.scopus.com/inward/record.url?scp=65549106823&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=65549106823&partnerID=8YFLogxK
U2 - 10.1016/j.bbamem.2009.01.015
DO - 10.1016/j.bbamem.2009.01.015
M3 - Article
C2 - 19366590
AN - SCOPUS:65549106823
SN - 0005-2736
VL - 1788
SP - 1332
EP - 1340
JO - Biochimica et Biophysica Acta - Biomembranes
JF - Biochimica et Biophysica Acta - Biomembranes
IS - 6
ER -