I don’t know, but here http://en.wikipedia.org/wiki/DNA#Altern … structures it sounds to me that the A-DNA is rather present in crystalographic studies.
Did they have it at such low resolution?
The "A" and "B" were arbitrary labels Rosie Franklin gave to the two types of DNA fibers she obtained under different conditions of salt concentration and relative humidity. She thought the A form was a potentially more interesting structure and wavered back and forth as to whether or not the A-form was helical, like the B-form clearly was. Franklin never received enough credit for her contributions.