select s1, byres (1vi9 within 3.5 of symp*)
select s2, byres (symp* within 3.5 of 1vi9)
color white, byres (s2 and (s1 around 3.5))
color white, byres (s1 and (s2 around 3.5))
show sticks, byres (s1 and (s2 around 3.5))
show sticks, byres (s2 and (s1 around 3.5))
distance hbonds, s1, s2, 3.5, 2