Chemistry Reference
In-Depth Information
NITRENIUM IONS AND RELATED
SPECIES IN PHOTOAFFINITY
LABELING
R. M
ARSHALL
W
ILSON AND
V
ALENTYNA
V
OSKRESENSKA
3.1 Introduction
3.2 Reactions of Nitrenium Ions with Biomolecules
3.2.1 Properties of Aryl Azides that Serve as Nitrenium Ion Precursors
3.3 Applications of Aryl Nitrenium Ions in Photoaffinity Labeling
3.3.1 4-Azido-2-nitrophenyl Amines
3.4 General Considerations
3.4.1 Purine Azides
3.5 Conclusions
References
3.1
INTRODUCTION
Photoaffinity labeling (PAL) has found increasing application as a tool for unraveling
the complex interactions of biological molecules. In general, a small, photoaffinity
labeling molecule is attached to a large biological molecule of interest (Fig. 3.1). It is
usually assumed that this small PAL molecule is unobtrusive and does not affect the
binding properties of the much larger biological molecule to which it is attached. The
labeled molecule is then exposed to a variety of other biomolecules with which it
might associate via various ephemeral noncovalent bonds such as hydrogen bonds,
electrostatic/ionic bonds, hydrophobic aggregation, and so on. Irradiation of this
