# Zoom in on a half-site
reset
rotate z 51
rotate y 11
rotate x -74
rotate z 25
# Zoom in one half-site
zoom 250
translate y 26
select all
hbonds off
restrict halfall
spacefill off
center (atomno=1844)                      
wireframe 80
select dna and halfall
color cpk
select major_groove and halfall
color brown
select minor_groove and halfall
color blue
set echo bottom
echo DNA: major groove brown, minor groove blue
hbonds on
hbonds 0.25
wireframe 150
backbone off
select halfall
zoom 250
# for some reason the zoom command seems to toggle