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