BUILD_EXTEND provides additional functions to BUILD block to enchance editing topology of the model.
"BUILD_EXTEND" menu block is loaded with MAIN_CMDS:load_build_extend.com.
Deletes the last picked atom (MAIN_CMDS:dele_atom.cmds). NO confirmation is required!
Deletes the last picked residue (MAIN_CMDS:dele_res.cmds). NO confirmation is required!
Two consecutive residues (of the two last picked atoms) can be joined (MERG_RES) (MAIN_CMDS:merge_res.cmds). This should be applied when ATTACHING N and C terminals to a peptide chain. NTER and CTER are namely attached to a residue as a new residue that should be later on merged (joined) to the original one.
Updates variable WORK_SEGM with segment names of all currently present atoms (MAIN_CMDS:update_segm.cmds)
Shows the value of variable WORK_SEGM.
> show vari WORK_SEGM
When the variable WORK_SEGM does not exist or it does not contain the segment names you want, your interaction with the program through the menu items will almost certainly result in NOTHING.
Clones the current "active" key atoms by making a copy and shifts them by a short distance. Useful during ab initio density interpretations when you simply want to apply the same topology a number of times (building beta strands or helical structures).
The macro is MAIN_CMDS:clone.cmds
Each time you have to provide (answer) with a new segment name and a sequence root.
Works well in combination with hydrogen bond constraints, when you for example "constrain" beta sheets arrangements with twist.