Only 4 of the 5 atoms of the deoxyribose sugar ring are close to being in the same plane. If we measure the angle between carbon atoms 1-2 and carbon atoms 3-4 with the dihedral angle tool as shown in the illustration, the angle of pucker in the ring is measured to be -25.97 degrees for the example chosen.

To measure the dihedral angle as shown:

1. Select the view "Sugar (deoxyribose)"
   
2. Click on the dihedral angle tool at the far right of the toolbar.
   
3. Click on the 4 consecutive carbon atoms of the sugar ring, beginning next to the oxygen atom.
   
4. Note the dihedral angle in the information box below the molecule.