Primary target pairing

Ionizing radiation arises from the photoelectric effect, the Compton effect, or ion pair production. Gamma radiation causes local and intense damage and may break chemical bonds. The primary target is the deoxyribonucleic acid (DNA) of the micro-organism. In addition, free radicals may be formed, such as peroxides that result in intracellular and extracellular peroxides by a chain reaction that causes damage. 

FIGURE 2.1 Examples of highly similar pairs of drugs designed to modulate the same primary targets. 

FIGURE 2.2 Typical examples of drug pairs where one modulates another s primary target as a side effect. 

Collectively, these thermal denaturation studies demonstrated that aPNAs bind to complementary ssDNA targets with high affinity and in a sequence-specific manner consistent with our proposed base-pairing model. Additional electrostatic and hydrophobic binding interactions can be incorporated into the aPNA design without affecting the primary Watson-Crick binding mode. 

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