cd D:\Bioinfa
load 3QTP.pdb, 3QTP
load 3qtp.omap, el-dens
remove chain B
remove resn HOH
remove resn 2PG
remove !(resi 431)
remove resn SO4
center resi 429:432 name ca 
set line_width, 10
isomesh new_map, el-dens, 1, chain A and resi 429:432 , carve=2