Structure of intact Thermus thermophilus V-ATPase by cryo-EM reveals organization of the membrane-bound V(O) motor.
The eubacterium Thermus thermophilus uses a macromolecular assembly closely related to eukaryotic V-ATPase to produce its supply of ATP. This simplified V-ATPase offers several advantages over eukaryotic V-ATPases for structural analysis and investigation of the mechanism of the enzyme. Here we report the structure of the complex at approximately 16 A resolution as determined by single particle electron cryomicroscopy (cryo-EM). The resolution of the map and our use of cryo-EM, rather than negative stain EM, reveals detailed information about the internal organization of the assembly. We could separate the map into segments corresponding to subunits A and B, the threefold pseudosymmetric C-subunit, a central rotor consisting of subunits D and F, the L-ring, the stator subcomplex consisting of subunits I, E, and G, and a micelle of bound detergent. The architecture of the V(O) region shows a remarkably small area of contact between the I-subunit and the ring of L-subunits and is consistent with a two half-channel model for proton translocation. The arrangement of structural elements in V(O) gives insight into the mechanism of torque generation from proton translocation.
Lau
Wilson C Y
WC
Molecular Structure and Function Program, The Hospital for Sick Children Research Institute and Department of Biochemistry, University of Toronto, Toronto, Ontario M5G 1X8, Canada.
Rubinstein
John L
JL
D002462:Cell Membrane / Q000378:metabolism*; D020285:Cryoelectron Microscopy; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D054730:Protein Interaction Domains and Motifs; D020836:Protein Structure, Quaternary; D021122:Protein Subunits / Q000737:chemistry / Q000378:metabolism; D011522:Protons; D016963:Thermus thermophilus / Q000201:enzymology*; D025262:Vacuolar Proton-Translocating ATPases / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure*
D021122:Protein Subunits; D011522:Protons; D025262:Vacuolar Proton-Translocating ATPases