BV_ExpressionBar

The BALLView expression bar

BALL expressions can be used for several purposes, e.g. to search, select, or match atom groups. The BALL expression bar enables the user to type such expression directly into the GUI. When pressing the Select button all matching atoms will be highlighted and selected in the Structures - window.
The Help button lists further information to BALL expressions.

Here are some examples for BALL expression. As example molecule we suggest to download 2hu4 chain A from the PDB.

• element(string) selects all elements of type "string" in the system, e.g., element(H)
• residueID(integer) selects the residue with the given ID number, e.g., try residueID(151) for 2hu4 and ASP in the binding pocket will the highlighted and selected.
• residue(string) selects all residues "string" in the system, e.g., residue(ARG)
• backbone() selects all backbone atoms of the system

All expressions can be combined using AND and OR operators, e.g.

• backbone() AND name(CA) selects all backbone C-alpha atoms (CA is the standard name for C-alpha atoms in BALL after application of the FragmentDB)