What are the similars and the differences of the A, B and Z forms of DNA ???

Hi leoteo75

The B, A and Z forms of DNA are three different conformations which
DNA can take. That is they are different shapes that otherwise
essentially identical DNA can form under different conditions. The B
form is probably the most common intracellular form of DNA. The A form
is created by dehydrating DNA and in hybrid DNA RNA pairs. The Z form
is left-handed rather than the usual right-handed conformation due to
methylation and may be important in DNA regulation.

For details see the folowing Wikipedia article, esp Different Helix Geometries:
http://en.wikipedia.org/wiki/B-DNA

also see DNA Secondary Structure here:
http://wine1.sb.fsu.edu/BCH4053/Lecture20/Lecture20.htm

you can also find more data and pictures of the different forma @
http://en.wikipedia.org/wiki/Z-DNA