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 exchangeallows 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 quenching by neighboring amino acids. Because of the large number of variables, we believe it is necessary to correlate data from a number of different proteins, as well as from different conformational states of each protein.

This poster presents results demonstrating that H/D exchange can be observed in multiple proteins by monitoring RTP lifetimes. In addition, the effect of the metal binding state of alkaline phosphatase upon its RTP lifetime and H/D exchange is presented.

G6PDH Hydrogen Exchange