Fig. 2.

iNicSnFR12 shows increased absorption at 450–520 nm upon nicotine binding. (A) Nicotine tartrate solution (1 mM) was added to the iNicSnFR solution (7.3 μM) to produce the indicated nominal [nicotine]. (B) Fitting the OD at 496 nm (the local peak absorption) to a single binding model yielded the parameters indicated