Z-DNA is a form of DNA in which the double helix winds to the left in a zig-zag pattern (instead of to the right, like the more common B-DNA form).
Z-DNA was discovered in 1979 by Alexander Rich and colleagues at MIT.
A algorithm for predicting the propensity of DNA to flip from the B-form to the Z-form, ZHunt, was written by Dr. P. Shing Ho in 1984. This algorithm was later developed by Tracy Camp , P. Christoph Champ , Sandor Maurice , and Jeffery M. Vargason for genome-wide mapping of Z-DNA (with P. Shing Ho as the principal investigator).
Representation of various forms of DNA
Comparison Geometries of Some DNA Forms
| Geometry attribute
| A-form
| B-form
| Z-form
|
| Helix sense | right-handed | right-handed | left-handed
|
| Repeating unit | 1 bp | 1 bp | 2 bp
|
| Rotation/bp | 33.6° | 35.9° | 60°/2
|
| Mean bp/turn | 10.7 | 10.0 | 12
|
| Inclination of bp to axis | +19° | -1.2° | -9°
|
| Rise/bp along axis | 2.3Å | 3.32Å | 3.8Å
|
| Pitch/turn of helix | 24.6Å | 33.2Å | 45.6Å
|
| Mean propeller twist | +18° | +16° | 0°
|
| Glycosyl angle | anti | anti | C: anti,
G: syn
|
| Sugar pucker | C3'-endo | C2'-endo | C: C2'-endo,
G: C2'-exo
|
| Diameter | 26Å | 20Å | 18Å
|
References
- P. Christoph Champ, Sandor Maurice, Jeffery M. Vargason, Tracy Camp, and P. Shing Ho. Distributions of Z-DNA and nuclear factor I in human chromosome 22: a model for coupled transcriptional regulation. Nucleic Acids Research , 2004 32(22):6501-6510.
