A-DNA and Z-DNA Atlases. Dave Ussery Comparative Microbial Genomics first lecture, 18 September, 2002. Outline. Helix family. A-DNA. A-DNA helix. A-DNA was the first DNA helix characterised by Rosalind Franklin in the early 1950’s. A-DNA helices
Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.
Comparative Microbial Genomics
first lecture, 18 September, 2002
Z-DNA was the first DNA helix to be crystallised
(in 1979), and came to the surprise of many biologists.
It is a thin, LEFT-HANDED helix, with 12 bp/turn,
and has a zig-zag backbone (hence its name). Certain
alternating pyrimidine/purine sequences
(e.g., CGCGCG) will form this helix.
Consider a stretch of purines (G or A, abbreviated R)
of length n:
What is the probability of finding this in a random DNA