  Despite a large body of work, the exact molecular details underlying
ion-selectivity and transport in the potassium channel have not been fully laid
to rest. One major reason has been the lack of experimental methods that can
probe these mechanisms dynamically on their biologically relevant time scales.
Recently it was suggested that quantum coherence and its interplay with thermal
vibration might be involved in mediating ion-selectivity and transport. In this
work we present an experimental strategy for using time resolved infrared
spectroscopy to investigate these effects. We show the feasibility by
demonstrating the IR absorption and Raman spectroscopic signatures of potassium
binding model molecules that mimic the transient interactions of potassium with
binding sites of the selectivity filter during ion conduction. In addition to
guide our experiments on the real system we have performed molecular
dynamic-based simulations of the FTIR and 2DIR spectra of the entire KcsA
complex, which is the largest complex for which such modeling has been
performed. We found that by combing isotope labeling with 2D IR spectroscopy,
the signatures of potassium interaction with individual binding sites would be
experimentally observable and identified specific labeling combinations that
would maximize our expected experimental signatures.
