Jagendorf. Andre

Electron-transferring molecules in the chain of carriers connecting PSII and PSI are oriented asymmetrically in the thylakoid membrane, so photoinduced electron flow results in the net movement of protons across the membrane, from the stromal side to the thylakoid lumen (Fig. 19-57). In 1966 Andre Jagendorf showed that a pH gradient across the thylakoid membrane (alkaline outside) could furnish the driving force to generate ATP. 

Observations in chloroplasts played a key role in the development of the chemiosmotic theory of oxidative phosphorylation, which we discussed in chapter 14. Andre Jagendorf and his colleagues discovered that if chloroplasts are illuminated in the absence of ADP, they developed the capacity to form ATP when ADP was added later, after the light was turned off. The amount of ATP synthesized was much greater than the number of electron-transport assemblies in the thylakoid membranes, so the energy to drive the phosphorylation could not have been stored in an energized... 

One of the most striking pieces of evidence in support of the chemiosmotic hypothesis was obtained in the 1960s by Andre Jagendorf and Ernest Uribe. When chloroplast lamellae are incubated in a solution at pH 4—in which case pH1 presumably attains a value near 4 — and then rapidly transferred to a solution with a pH° of 8 containing ADP and phosphate, the... 

In 1966, Andre Jagendorf showed that chloroplasts synthesize ATP in the dark when an artificial pH gradient is imposed across the thylakoid membrane. To create this transient pH gradient, he soaked chloroplasts in a pH 4 buffer for several hours and then rapidly mixed them with a pH 8 buffer containing ADP and Pj. The pH of the stroma suddenly increased to 8, whereas the pH of the thylakoid space remained at 4. A burst of ATP synthesis then accompanied the disappearance of the pH gradient across the thylakoid membrane (Figure 19.24). This incisive experiment was one of the first to unequivocally support the hypothesis put forth by Peter Mitchell that ATP synthesis is driven by proton-motive force. 

Fig. 2. Franck Condon principle as applied to carotenoids. The photograph of James Franck, the co-di scoverer of the principle is shown as an inset, and was taken by the author in 1963 when Franck attended the Airlie House Conference on Photosynthetic Mechanisms of Green Plants, organized by Bessel Kok and Andre Jagendorf.

The antibody binding and detection are described in Materials and Methods. S, spinach CFi C, C. reinhardi CFj. Antibodies to 6. reinhardi CFi and its a subunit were raised in rabbits. Antiserum against the 3 subunit of spinach CF was a gift from Dr. Andre T. Jagendorf. 

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