load ==1TRO.pdb
select all
color cpk 
wireframe 50
cartoons off
cpk off

pause

restrict dna
wireframe 50
cpk off
define seto4 *.o4*
define setop *.OP?
define setn *.N? and dna

pause

select seto4
cpk 200
color orange

pause

select seto4
color cpk
cpk off
select setop
cpk 200
color lightgreen

pause

select setop
color cpk
cpk off
select setn
cpk 200
color green