抄録
A DNA molecule is not a simple featureless rod but it takes a characteristic conformation depending on its base sequence as well as on its molecular environment. Each feature is likely to be recognized by a specific protein. In principle, the DNA molecule exists as a double helical B form, which is a majour target of DNA-binding proteins. Even in the B form it can bend with or without proteins. In addition, various DNA structures including a single-standed stable mini-hairpin, double helical Z and A forms, a triple helix and a quadruple helix have been observed.
