Ions are essential component of the cell and frequently are found bound to various macromolecules,
in particular to proteins. A binding of an ion to a protein greatly affects proteins biophysical
characteristics and needs to be taken into account in any modeling approach. However, ion’s bounded
positions cannot be easily revealed experimentally, especially if they are loosely bound to
macromolecular surface. The BION-2 web server predicts non-specifically surface-bound ions. The BION-2 is easy to use web server that requires
only coordinate file to be inputted, and the user is provided with various, but easy to navigate, options. The coordinate file with predicted bound ions is displayed on the output and is available for download.