zap
define o_drib (*.O?* and DNA)
define c_drib (*.C?* and DNA)
define o_phos (*.O?P and DNA)
define p_phos (*.P and DNA)
define polar_big (DA*.N3 or DA*.N1 or DC*.N4 or DT*.O4 or DG*.N1 or DG*.N2 or DG*.N3 and DNA)
define not_big (DA*.C4 or DA*.C2 or DC*.C4 or DT*.C4 or DT*.C5 or DT*.C6 or DT*.C5M or DG*.C2 or DG*.C4 or DG*.C6 and DNA) 
define polar_small (DA*.N6 or DA*.N7 or DC*.O2 or DT*.O2 or DG*.N7 or DG*.N9 and DNA) 
define not_small (DA*.C5 or DA*.C6 or DA*.C8 or DC*.C2 or DT*.C2 or DG*.C8 and DNA) 

