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 is quite different from the right-handed forms. Z-DNA is often compared against B-DNA in order to illustrate the major differences. This unique type of DNA can form alternating purine-pyrimidine tracts under very specific conditions. These conditions include high salt, the presence of some cations, and DNA supercoiling.
An algorithm for predicting the propensity of DNA to flip from the B-form to the Z-form, Z-Hunt, was written by Dr. P. Shing Ho in 1984. This algorithm was later developed by Tracy Camp, P. Christoph Champ, Sandor Maurice, and Jeffrey M. Vargason for genome-wide mapping of Z-DNA (with P. Shing Ho as the principal investigator). Z-Hunt is available at Z-Hunt online.
After 26 years of attempts, Rich et al. finally crystalised the junction box of B- and Z-DNA. Their results were published in an October 2005 Nature journal. Whenever Z-DNA forms, there must be two junction boxes that allow the flip back to the canonical B-form of DNA.
Representation of various forms of DNA
Comparison Geometries of Some DNA Forms
|Repeating unit||1 bp||1 bp||2 bp|
|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,|
|Sugar pucker||C3'-endo||C2'-endo|| C: C2'-endo,|
- Wang AHJ, Quigley GJ, Kolpak FJ, Crawford JL, van Boom JH, Van der Marel G, and Rich A (1979). Molecular structure of a left-handed double helical DNA fragment at atomic resolution. Nature (London), 282:680-686
- Champ PC, Maurice S, Vargason JM, Camp T, and Ho PS (2004). Distributions of Z-DNA and nuclear factor I in human chromosome 22: a model for coupled transcriptional regulation. Nucleic Acids Research, 32(22):6501-6510
- Ha SC, Lowenhaupt K, Rich A, Kim YG, and Kim KK (2005). Crystal structure of a junction between B-DNA and Z-DNA reveals two extruded bases. Nature 437:1183-1186
- Rich A, Zhang S (2003). Timeline: Z-DNA: the long road to biological function. Nat Rev Genet, 4(7):566-72.
- Gagna CE, Lambert WC (2003). The halting arrival of left-handed Z-DNA. Med Hypotheses, 60(3):418-23.
- General references
- Ha SC, Lowenhaupt K, Rich A, Kim YG, and Kim KK (2005). Crystal structure of a junction between B-DNA and Z-DNA reveals two extruded bases. Nature 437:1183-1186.
- Champ PC, Maurice S, Vargason JM, Camp T, and Ho PS (2004). Distributions of Z-DNA and nuclear factor I in human chromosome 22: a model for coupled transcriptional regulation. Nucleic Acids Research, 32(22):6501-6510.
- Eichman BF, Schroth GP, Basham BE, and Ho PS (1999). The intrinsic structure and stability of out-of-alternation base pairs in Z-DNA. Nucleic Acids Res, 27(2):543-550.
- Ho PS (1994). The non-B-DNA structure of d(CA/TG)n does not differ from that of Z-DNA. Proc Natl Acad Sci USA, 91(20):9549-9553.
- Sniden RR (1994). DNA structure and function. Academic Press, 179-216.
- Kagawa TF, Howell ML, Tseng K, and Ho PS (1993). Effects of base substituents on the hydration of B- and Z-DNA: correlations to the B- to Z-DNA transition. Nucleic Acids Res, 21(25):5978-5986.
- Ellison MJ, Fenton MJ, Ho PS, and Rich A (1987). Long-range interactions of multiple DNA structural transitions within a common topological domain. EMBO J, 6(5):1513-1522.
- Ho PS, Ellison MJ, Quigley GJ, and Rich A (1986). A computer aided thermodynamic approach for predicting the formation of Z-DNA in naturally occurring sequences. EMBO J, 5(10):2737-2744.
- Kelleher RJ 3rd, Ellison MJ, Ho PS, and Rich A (1986). Competitive behavior of multiple, discrete B-Z transitions in supercoiled DNA. Proc Natl Acad Sci USA, 83(17):6342-6346.
- Ho PS, Frederick CA, Quigley GJ, van der Marel GA, van Boom JH, Wang AH, and Rich A (1985). G.T wobble base-pairing in Z-DNA at 1.0 A atomic resolution: the crystal structure of d(CGCGTG). EMBO J, 4(13A):3617-3623.
- Wang AHJ, Quigley GJ, Kolpak FJ, Crawford JL, van Boom JH, Van der Marel G, and Rich A (1979). Molecular structure of a left-handed double helical DNA fragment at atomic resolution. Nature (London), 282:680-686.