load 3OES.pdb
set antialias, 1
set light_count, 1
set ambient, 0.25
set mesh_width, 0.6
color violet, chain A
symexp sym, 3OES, 3OES, 5
show cartoon
color red, sym*
select 3OES 
hide lines
show cartoon
select set1, byres (3OES within 3.5 of sym*)
select set2, byres (sym* within 3.5 of 3OES)
color white, byres (set2 and (set1 around 3.5))
color white, byres (set1 and (set2 around 3.5))
show sticks, byres (set1 and (set2 around 3.5))
show sticks, byres (set2 and (set1 around 3.5))
distance hbonds, set1, set2, 3.5, 2
png symex.png