Mechanism of inhibition of the V-type molecular motor by tributyltin chloride.
Tributyltin chloride (TBT-Cl) is an endocrine disruptor found in many animal species, and it is also known to be an inhibitor for the V-ATPases that are emerging as potential targets in the treatment of diseases such as osteoporosis and cancer. We demonstrated by using biochemical and single-molecular imaging techniques that TBT-Cl arrests an elementary step for rotary catalysis of the V(1) motor domain. In the presence of TBT-Cl, the consecutive rotation of V(1) paused for a long duration ( approximately 0.5 s), even at saturated ATP concentrations, and the pausing positions were localized at 120 degrees intervals. Analysis of both the pausing time and moving time revealed that TBT-Cl has little effect on the binding affinity for ATP, but, rather, it arrests the catalytic event(s). This is the first report to demonstrate that an inhibitor arrests an elementary step for rotary catalysis of a V-type ATP-driven rotary motor.
Takeda
Mizuho
M
Chemical Resources Laboratory, Tokyo Institute of Technology, Yokohama, Japan.
Suno-Ikeda
Chiyo
C
Shimabukuro
Katsuya
K
Yoshida
Masasuke
M
Yokoyama
Ken
K
D000255:Adenosine Triphosphate / Q000378:metabolism; D055162:Biocatalysis / Q000187:drug effects; D052244:Endocrine Disruptors / Q000633:toxicity*; D007700:Kinetics; D009068:Movement; D017434:Protein Structure, Tertiary; D012399:Rotation; D016963:Thermus thermophilus / Q000201:enzymology*; D014220:Trialkyltin Compounds / Q000633:toxicity*; D025262:Vacuolar Proton-Translocating ATPases / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism
D052244:Endocrine Disruptors; D014220:Trialkyltin Compounds; C011559:tributyltin; D000255:Adenosine Triphosphate; D025262:Vacuolar Proton-Translocating ATPases