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Different forms of DNA

Most of the biologically active DNA exists in the Watson -Crick helical form. This is the B-form of DNA. The double helix is able to assume other forms, depending upon varying environmental conditions.
Forms of DNA
  • 6 different morphological forms of DNA : A,B,C,D,E & Z
  • A,B,C & D are right handed helices
  • B & Z occur in rigidly controlled experimental conditions
  • A-DNA is the dehydrated form which occurs in an environment richer in Na+ & less of water
  • B-DNA occurs under salt concentration  & high degree of hydration
  • C-DNA & E-DNA are seen under special environmental condition &have slightly different conformation so do not occur  in vivo
  • Z-DNA is left handed helices. Z-DNA, is the skinniest DNA, with only one groove and is stabilized by high salt concentration.

Different forms of DNA
B-DNA, A-DNA  and Z-DNA

Comparison chart:  B, A & Z DNA


Different forms of DNA
Comparison Chart- B-DNA, A-DNA, and Z-DNA
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