Opening Image: A-, B- and Z-DNA. Each double-stranded structure contains 14 Watson-Crick base pairs.
backbone traces. Both the A- and B-DNA are right-handed helices. Remember the sense of a helix is intrinsic (it does not depend on the end from which it is viewed). For a right-handed helix, the strands rotate in a clockwise direction as they move away from you. alternate views.
base stacking in the different helices.