First evidence to show the topological change of DNA from B-dNA to Z-DNA conformation in the hippocampus of Alzheimer's brain.

Alzheimer's disease (AD) is a complex neurodegenerative disorder. Our studies for the first time showed evidence for altered DNA conformation in the hippocampus of Alzheimer's disease affected brain. The Circular dichroism spectra of severely affected AD DNA showed a typical left-handed Z-DNA conformation, whereas normal, young, and aged brain DNA have the usual B-DNA conformation. Moderately affected AD DNA has modified B-DNA conformation (probable B-Z intermediate form). The ELISA, ethidium bromide binding pattern to DNA and melting temperature (Tm) profiles also revealed the conformational transition from B to Z DNA in AD brain DNA. The altered conformation of DNA will have tremendous implications in gene expressions.