Question

is z form of DNA present in all organisms?

Answer 1

Z-DNA is present and form and shape has been established. It is a kind of DNA with alternating strands of pyrimidines and purines. THough it does form a molecule of DNA with the bases forming different angles from the zero degree plane of base pairs. Such a molecule would't be producing protiens, that is the amino acids formed by this DNA's basepairs would be not functional. So I say that it wouldn't be found in any organisms.22 minutes ago

Answer 2

I do agree with armstrong. However, I would guess that DNA structures other than the native are often induced in a variety of other interactions that it does with proteins that bind to it. Z-DNA is a form of DNA which often forms by stretches of alternating R and Y residues but there has been some evidence of it being induced in Small acid Soluble proteins (SAPs) when the bind to DNA. It is also an understanding that they might be important during transcription where the DNA being immediately read assumes Z-DNA-like conformation.

This would hold for most DNA conformations, which are induced and form local such interactions instead of a long thread of an odd helical shape.

Hope that helps.