Introduction

Many hydrogens from both the peptide-amino group and polar side chains in the protein structure continually exchange with solvent hydrogens.  The wide dynamic range of kinetics observed for these exchange reactions offers information about the local structure and the solvent accessibility of those groups in the protein.  The traditional method of measuring this exchange has been through nuclear magnetic resonance (NMR). However, our group has  recently shown that it is also possible to observe the reaction of hydrogen/deuterium (H/D) exchange through room temperature phosphorescence (RTP) measurements.  The ability of RTP to monitor H/D exchange allows for the study of this phenomenon with larger and more complicated proteins which are not easily studied with NMR.

In addition, by using H/D exchange we will be able to learn more about the fundamentals governing RTP and therefore how to apply RTP techniques to gather more specific information about protein structure on both a global and local scale. It is postulated that the RTP lifetime of a tryptophan is a function of many variables including the local structural rigidity and the presence of nearest neighbor quenching amino acids. These relationships, however, are still not well understood and studying the relationship between H/D exchange and RTP is expected to provide ore insight into the fundamentals governing tryptophan phosphorescence.

Local Environment of W109 in AP