Editor's Summary
20 October 2005
The B to Z of DNA
The existence of left-handed DNA (or Z-DNA) was reported in 1979, and marked by a Nature cover. This week's cover story is the determination of the crystal structure of the junction between left-handed DNA and 'normal', right-handed DNA or B-DNA. Each time a DNA segment turns to Z-DNA, two of these B–Z junctions are created. Z-DNA often forms transiently during transcription and other physiological processes, then relaxes to the less energetic B form. The three-dimensional structure shows that the junction is very tight, and that a base pair is pushed out of the double helix, one base on each side of the junction. This adjustment maintains the base stacking that is a major stabilizing factor. These displaced bases may be sites for DNA modification. On the cover, a molecule containing a B–Z junction is shown in the centre, with Z-DNA, naturally, to the left and B-DNA to the right.
News and Views: Molecular biology: DNA twists and flips
DNA can shape itself into many forms to achieve its purposes in life. The crystal structure of the junction between two of its forms provides insight into how DNA might accomplish some of these acrobatics.
Richard R. Sinden
doi: 10.1038/4371097a
Letter: Crystal structure of a junction between B-DNA and Z-DNA reveals two extruded bases
Sung Chul Ha, Ky Lowenhaupt, Alexander Rich, Yang-Gyun Kim and Kyeong Kyu Kim
doi: 10.1038/nature04088
First paragraph | Full Text | PDF (405K) | Supplementary information
