zap
load 1D5Y_mod.pdb

define set1 *.O?* and dna
define set2 *.O?P
define set3 dna and *.N?
echo 1. all structure
pause

restrict dna
zoom 150
wireframe 
echo 2. dna

pause

select set1
cpk 150
echo 3. oxygen in 2'-desoxyriboses
pause

cpk off
select set2
cpk 150
echo 4. oxygen in phosphates

pause

cpk off
select set3
cpk 150
echo 5. nitrogen in bases