Principles of Fluorescence Spectroscopy

78 FLUOROPHORES
Figure 3.26. HIV integrase assay based on release of the isoxanthopterin-containing
nucleotide (F). Revised from [87], and reprinted
with permission of Oxford University Press.
on DNA structure was used as an assay for the HIV integrase
protein. This protein is responsible for integration of
HIV DNA into the host cell's genome. 89–90 The assay was
based on a DNA oligonucleotide that has the sequence specific
for HIV integrase (Figure 3.26). The enzyme mechanism
involves cleavage of a dinucleotide from the 3'-end of
HIV DNA, followed by ligation to the 5'-end of the host
DNA. The IXP nucleotide was positioned near the 3'-end of
the synthetic substrate. Incubation with HIV integrase
resulted in release of the dinucleotide, which was detected
by an increase in IXP fluorescence.
3.5. CHEMICAL SENSING PROBES
Figure 3.27. Chemical sensing probes (left) and thus spectra (right).
It is often desirable to detect spectroscopically silent substances
such as Cl – ,Na + , or Ca 2+ . This is possible using