subroutine char SEGMENTS

set vari TEST_ATOM int =   -1
if ( nathis .gt. 0 ) then
set vari TEST_ATOM int atoms sele atom numb $1 end
end_if
show vari TEST_ATOM

if ( AUTO_SEL .eq. "HISTORY" ) key XX_KEY sele by resi atom numb $1 end
if ( AUTO_SEL .eq. "ACTIVE" ) key XX_KEY sele by resi active end
if ( AUTO_SEL .eq. "WORK" ) key XX_KEY sele  segm name SEGMENTS end
key PASS_KEY sele by bond XX_KEY end
key PASS_KEY sele by residue PASS_KEY end

set vari ITES = -1
set vari ITEST int atom sele  XX_KEY .a atom name CA CB N O C H end
show vari ITEST
if ( ITEST .le. 0 ) then
echo MAIN_CMDS:trace_side.cmds NO MAIN CHAIN or EMPTY SELECTION ?
return
end_if

key OLD sele all end
dele atom sele segm name HE_X SIDE end
dele atom sele XX_KEY .a .not atom name CA CB N O C H end

! set vari WORK_SEGM global = HELP
set vari MAP_SIDE = nmaps + 1
show box sele XX_KEY end
show key
make map from MAP_ACT init 0 integer around 8 sele XX_KEY end 
if ( MAP_SIDE .ne. nmaps ) return
show key XX_KEY
trace side map MAP_ACT cont MAP_CONT - 0.3 work_map MAP_SIDE \
      sele XX_KEY end sele XX_KEY .o segm name WORK_SEGM end \
      step 30 \
      residue "SP3 SP2 RN5 RN6" segment SIDE \
      test TEST_ATOM

dele map MAP_SIDE
! .or. segm name SIDE 
key entity sele by segm XX_KEY end 

show key XX_KEY
show key entity

  key old sele all end
  make resi sele entity .o segm name SIDE end root CA
  rena segm HE_X sele entity end

! read file MAIN:top/targets_ac.pdb coor pdb
! read file MAIN:top/targets_ac.ctab ctab first sele segm name TARG end
! 
!  find names sele .n old .a .n  segm name TARG end sele segm name TARG end
! 
! dele atom sele entity .or. segm name TARG end


! key XX_KEY drop
! key PASS_KEY drop
< MAIN_CMDS:re_image.cmds WORK_SEGM
! image sele segm name HELP .a atom name CA end col 220 resi name
image hist init
<DEF_ALL WORK_SEGM
return