Rotation of artificial rotor axles in rotary molecular motors.
F1- and V1-ATPase are rotary molecular motors that convert chemical energy released upon ATP hydrolysis into torque to rotate a central rotor axle against the surrounding catalytic stator cylinder with high efficiency. How conformational change occurring in the stator is coupled to the rotary motion of the axle is the key unknown in the mechanism of rotary motors. Here, we generated chimeric motor proteins by inserting an exogenous rod protein, FliJ, into the stator ring of F1 or of V1 and tested the rotation properties of these chimeric motors. Both motors showed unidirectional and continuous rotation, despite no obvious homology in amino acid sequence between FliJ and the intrinsic rotor subunit of F1 or V1 These results showed that any residue-specific interactions between the stator and rotor are not a prerequisite for unidirectional rotation of both F1 and V1 The torque of chimeric motors estimated from viscous friction of the rotation probe against medium revealed that whereas the F1-FliJ chimera generates only 10% of WT F1, the V1-FliJ chimera generates torque comparable to that of V1 with the native axle protein that is structurally more similar to FliJ than the native rotor of F1 This suggests that the gross structural mismatch hinders smooth rotation of FliJ accompanied with the stator ring of F1.
['Baba|Mihori|M|', 'Iwamoto|Kousuke|K|', 'Iino|Ryota|R|0000-0003-0110-5704', 'Ueno|Hiroshi|H|', 'Hara|Mayu|M|', 'Nakanishi|Atsuko|A|', 'Kishikawa|Jun-Ichi|JI|', 'Noji|Hiroyuki|H|', 'Yokoyama|Ken|K|']
D000595:Amino Acid Sequence D001426:Bacterial Proteins D008958:Models, Molecular D020409:Molecular Motor Proteins D011336:Probability D021122:Protein Subunits D006180:Proton-Translocating ATPases D011994:Recombinant Proteins D012399:Rotation D016415:Sequence Alignment D013997:Time Factors D019415:Torque D025262:Vacuolar Proton-Translocating ATPases
rotary molecular motor F1 ATPase V-ATPase protein design