Figure 5

EIS investigation on human OR 17-40. Nyquist plot for the human OR 17-40 in the absence and in the presence of specific ligands (heptanal and helional molecules). The impedances are normalized to the static value of the native state Z _real (0). In the upper figure, symbols report experiments carried out with a standard three electrode electrolytic cell sketched on the right-hand side part of the figure (with WE, working electrode; CE, counter electrode; RE, reference electrode). Here, crosses refer to the absence of an odorant and empty (full) squares to the presence of an heptanal (helional) odorants at concentration of 10⁻¹⁰M. In the lower part of the figure, lines report theoretical results with the continuous curve referring to the native state configuration with R _C  = 70 Å and the dashed line referring to the active state configuration with R _C  = 46 Å[3].