Structural study on the architecture of the bacterial ATP synthase Fo motor.
We purified the F(o) complex from the Ilyobacter tartaricus Na(+)-translocating F(1)F(o)-ATP synthase and performed a biochemical and structural study. Laser-induced liquid bead ion desorption MS analysis demonstrates that all three subunits of the isolated F(o) complex were present and in native stoichiometry (ab(2)c(11)). Cryoelectron microscopy of 2D crystals yielded a projection map at a resolution of 7.0 Å showing electron densities from the c(11) rotor ring and up to seven adjacent helices. A bundle of four helices belongs to the stator a-subunit and is in contact with c(11). A fifth helix adjacent to the four-helix bundle interacts very closely with a c-subunit helix, which slightly shifts its position toward the ring center. Atomic force microscopy confirms the presence of the F(o) stator, and a height profile reveals that it protrudes less from the membrane than c(11). The data limit the dimensions of the subunit a/c-ring interface: Three helices from the stator region are in contact with three c(11) helices. The location and distances of the stator helices impose spatial restrictions on the bacterial F(o) complex.
Department of Structural Biology,  Max Planck Institute of Biophysics, 60438 Frankfurt/Main,  Germany.
Jonna K
JK
Hakulinen
Adriana L
AL
Klyszejko
Jan
J
Hoffmann
Luise
L
Eckhardt-Strelau
Bernd
B
Brutschy
Janet
J
Vonck
Thomas
T
Meier
D020285:Cryoelectron Microscopy; D003460:Crystallization; D045182:Fusobacteria / Q000201:enzymology*; D007150:Immunohistochemistry; D013058:Mass Spectrometry; D018625:Microscopy, Atomic Force; D008958:Models, Molecular; D011487:Protein Conformation; D021122:Protein Subunits / Q000737:chemistry; D006180:Proton-Translocating ATPases / Q000737:chemistry* / Q000302:isolation & purification
D021122:Protein Subunits; D006180:Proton-Translocating ATPases