YOSHIDA AND HISABORI LABORATORY WEB SITE
This Japanese laboratory has studied the ATP synthase from a thermophilic bacterium and from thylakoid membranes of plant chloroplasts. These workers produced the experimental evidence that ATP synthase is a rotary motor, thereby confirming the binding change hypothesis that Paul Boyer put forward in 1997. The visualization of the rotation of the γ subunit in the central cavity of the ATPase used fluorescently labeled actin filaments. These impressive results influenced the Nobel prize selection for Walker and Boyer. This experiment also opened a new field of single-molecule bioenergetics so the seminal nature of this achievement makes this web site both motivational and informative for students. There is a well chosen amount of introductory text including the assertion that “One person produces and consumes his or her own body weight in ATP in a day.” This obliged me to scribble a calculation (using Mr ATP = 507) that implied that this was at least close. There are so many ways of arriving at an answer to this problem that it should make a good class exercise to calculate ATP turnover per day. Continuing from this we are told that such rapid turnover of ATP is supported by the efficient production of ATP in mitochondria and that similar enzymes are working in plant chloroplasts and bacterial cell membranes. After working through “ATP synthase—the rotary engine in the cell” you can read some brief notes on “The Proteins Caretakers: Molecular Chaperones” and “Regulatory mechanism of the various enzymes.” For lecturing you may care to download a copy of the video showing the rotating actin filament. I have found that this direct visual evidence for the way that molecules work in biochemistry makes a valuable impression on undergraduates. If you want to delve into greater structural complexity of the ATPase then try nature.berkeley.edu/∼hongwang/.