Minor and major groove widths: direct P-P distances and refined P-P distances
   which take into account the directions of the sugar-phosphate backbones

   (Subtract 5.8 Angstrom from the values to take account of the vdw radii
    of the phosphate groups, and for comparison with FreeHelix and Curves.)

Ref: M. A. El Hassan and C. R. Calladine (1998). ``Two Distinct Modes of
     Protein-induced Bending in DNA.'' J. Mol. Biol., v282, pp331-343.

                  Minor Groove        Major Groove
                 P-P     Refined     P-P     Refined
   1 GA/UC       ---       ---       ---       ---
   2 AG/CU       ---       ---       ---       ---
   3 GG/CC      17.9       ---      16.9       ---
   4 GG/CC      17.0      15.3      17.4      14.8
   5 GC/GC      17.0      15.3      16.2      14.5
   6 CG/CG      17.2      15.8      14.7      10.4
   7 GG/CC      16.7      15.2      16.4      13.7
   8 GG/CC      16.2       ---      16.1       ---
   9 Gu/AC       ---       ---       ---       ---
  10 uP/GA       ---       ---       ---       ---
  11 PC/GG       ---       ---       ---       ---
  12 CC/GG       ---       ---       ---       ---
  13 CC/GG       ---       ---       ---       ---
  14 CG/GG      17.1       ---       8.0       ---
  15 GA/UG       ---       ---       ---       ---
  16 AG/CU       ---       ---       ---       ---
  17 GG/CC       ---       ---       ---       ---
  18 GA/UC       ---       ---       ---       ---
  19 AG/CU       ---       ---       ---       ---
  20 GG/CC       ---       ---       ---       ---
  21 GG/CC      17.0       ---      18.9       ---
  22 GG/UC      16.9       ---      17.6       ---
  23 GG/CU       ---       ---       ---       ---
  24 GG/CC       ---       ---       ---       ---