Supplementary Figure 8: Fluorescence properties of L-Anap.
From: The HCN channel voltage sensor undergoes a large downward motion during hyperpolarization
a, Emission spectra of free L-Anap in different solvents. Insert: overlap of spectra in the different solvents illustrates that the shape of the spectra is not appreciably affected by these different solvents. b, Emission spectra of L-Anap using the spectrograph attached to the patch-clamp microscope, using different slit widths. Slit 1 width: 5.9 µm; slit 2 width: 10.7 µm; slit 3 width: 24.8 µm. The shape of the spectra is not appreciably affected by different slit widths up to 25 µm, much larger than the diameter of our patches. c, Absorption spectra of free L-Anap in different solvents. The spectra were normalized to the extinction coefficient (17,500 M-1 cm-1) of L-Anap in EtOH at 360 nm as previously reported by Chatterjee et al. 2013. In our estimates of the quantum yield of Anap incorporated into the channel, we assume the environmental change in fluorescence intensity was entirely due to a change in quantum yield and not extinction coefficient.
