The difference between the earlier interpretation and the current thought is essentially the order in which the early events occur. It is highly likely then that what Sir George Porter’s group, measured in London, was the total time, including excitation energy migration among the ensemble of ancillary Chls in the RC preparations. We had proposed BIX 1294 concentration sharing RC preparations between our two groups at the time, but that unfortunately never happened. New research (from Van Grondelle’s group; see Groot et al. 2005) indicates that the first charge separation event occurring between ChlD1 and PheoD1

may be very fast (<1 ps). However, on the basis of their experiments, Holzwarth et al. (2006) considered 3 ps to be the Selleck GDC-0449 value for this event. This is followed by secondary positive charge transfer from to ChlD1 to PD1, which in all likelihood, takes place within 3–8 ps. Detailed interpretations are still quite complex and open to debate (see a review by Renger and Holzwarth 2005). However, we note that Riley et al. (2004) provided evidence for highly dispersive primary charge separation kinetics and gross heterogeneity in isolated PS II RCs that were in agreement with Alfred Holzwarth’s data. Novoderezhkin et al. (2007) have proposed that there may be mixing of exciton and charge-transfer states in PS II RCs. Probably there is not ‘one’ charge separation time/process in PS II,

but CX-5461 in vivo several depending (particularly at low temperature) on the amount of inhomogeneous broadening. Furthermore, the rates of these processes may depend upon excitation wavelength, and this also complicates interpretation. Precise resolution of the events occurring in femtoseconds Protein kinase N1 to picoseconds certainly requires additional measurements with PS II in vivo, not just in isolated RCs, as well as new theory. We certainly had great fun doing the experiments described above. MS would bring the samples from Golden, CO; G would drive up to Argonne National Lab and handle the samples with MS; and MW with his

associates would be ready for us with their instruments all set to go. We would have lunch together at the Argonne Cafeteria or an outstanding local ‘dive’ that served amongst the world’s best burritos. We would also go out for dinner together at a nearby Japanese restaurant (Yokohama), where sushi and shashimi would end a long day in the lab! G also remembers using a long table outside the Lab to lie down and rest during late night runs. MS remembers the power outages, air conditioning problems, and the sudden inconvenient appearance of the ‘Tiger Team’ of US Department of Energy (DOE) at the door of MW’s laser lab. (In 1991, such teams were known to perform intense and detailed safety inspection of all the DOE laboratories.) Nevertheless, we surmounted these problems, though they were sources of some frustration at the time, wrote papers together, exchanged drafts, and answered reviewers’ comments.