How is Z-DNA different from other forms of DNA?

Z-DNA has a structure that’s radically different from other forms of DNA in several aspects. 

Z-DNA has a left-handed double helix structure with a pronounced zigzag pattern in the phosphodiester backbone. This zigzag appearance of the backbone is what immediately sets it apart from other forms of DNA. 

The structure consists of major and minor grooves that show little difference in width, unlike that of A-DNA and B-DNA. 

The width of the helix in Z-DNA is 1.8nm, which is narrower than other forms of DNA. 

Z-DNA is inherently unstable. It appears as a transient structure occasionally induced by certain biological activities but disappears quickly. Its inherent instability and transient nature makes the study of Z-DNA more challenging.