define polar oxygen, nitrogen
define nepolar carbon, *.P, sulphur
define dnk :T, :U
define polar_dna polar and dnk and within(3.5, (protein and polar))
define nepolar_dna nepolar and dnk and within(4.5, (protein and nepolar))
define riboza (*.C1*, *.C2*, *.C3*, *.C4*, *.C5*, *.O4*)
define fosfat (*.P, *.O1P, *.O2P, *.O3*, *.O5*)
define ao (*.N1, *.C6, *.C5, *.C4, *.N3, *.C2, *.O2, *.N4, *.C7, *.O4, *.N9, *.C8, *.N7, *.N6, *.N2, *.O6) and (purine, pyrimidine)

select dnk
cpk off
wireframe 50


cpk off
select polar_dna and riboza
cpk 150




cpk off
select nepolar_dna and riboza
cpk 150




cpk off
select polar_dna and fosfat
cpk 150




cpk off
select nepolar_dna and fosfat
cpk 150



cpk off
select polar_dna and ao
cpk 150




cpk off
select nepolar_dna and ao
cpk 150
