Dear Colleagues -

I found myself confused on a rather basic issue. I always thought that:

1. FRET requires that the acceptor only absorbs, not necessarily fluoresces (and that seems to be correct: Ganesan et al, PNAS, 2006, vol 103, 4089-94)
2. Bleaching of fluorophores mostly affects the quantum yield, not the absorption (cannot find any specific information on this subject, other than the molecule gets "damaged")

But then it's not clear how the acceptor photobleaching method would work if the acceptor absorption remains intact.  So is it the absorption that gets destroyed in photobleaching? Or both?

Thank you

Mike Model
Kent State University