Illustration of the relationship between BI- or BII-rich regions and DNA grooves.
The BI-rich (PDB code 1EHV, left) and BII-rich (PDB code 3GGI, right) decamer X-ray structures are in the same orientations. BI and BII phosphate groups are in blue and green, respectively. Top: the lateral view shows that the minor groove (mG) is considerably enlarged in the BII-rich structure (right). Bottom: view along the major groove (MG), showing its reduced concavity in the BII-rich structure (right).