The objective of the proposed interdisciplinary research program is to describe, at the atomic level, the
structural and dynamic determinants of function and dysfunction in biological ion binding domains.
Essentially all aspects of cellular metabolism are regulated by signaling proteins that respond to
millisecond, nM-M transients in [Ca2+] while rejecting the effects of other ions present in thousand- to
million-fold excess. Finely tuned binding sites mediate these critical processes. Mutations that perturb their
coordination shells are disproportionately associated with a range of diseases including cancer, diabetes,
and heart disease. Nevertheless, characterization of binding site architectures often remains limited to
static crystallographic structures, and – even for the most-studied signaling proteins – large gaps remain in
knowledge of the sequences leading from ion binding to downstream signal transduction. To address this
deficiency, it is necessary to deploy experimental methods that simultaneously provide time resolution and
structural sensitivity. The proposed interdisciplinary research approach aims to characterize the structure
and activity of ion binding domains and proteins using a suite of infrared spectroscopic techniques and
supporting computational tools. Specifically, steady-state (Fourier transform infrared) and nanosecond
time-resolved (quantum cascade laser time resolved infrared) spectroscopy will be used to characterize
the binding geometries and conformational transitions that typify both wild-type and disease-associated ion
binding domains under physiologically relevant conditions. Both electronic structure calculations and
molecular dynamics simulations will provide atomistic interpretations of the resulting spectroscopic
datasets.
