Read for comprehension: DNA structure is dynamic. Evidence suggests the possibility that variations in structural properties depending on base sequence such as the rotation angle between residues and base roll might serve as conformational targets for proteins. Of the three forms, A-DNA. B-DNA (Watson-Crick form) and Z-DNA, B-DNA is by far the most commonly seen in the biological context. The B-DNA helix has a major and minor groove, an important structural feature for DNA-protein interactions.