Use the right button to obtain a menu and then select

"Measurements" followed by selecting "Click for distance

measurements". The thin red lines link the atoms of interest

1. Measure the distance between the sulfonamide nitrogen and

   the zinc atom. This represents a metal-ion interaction.

   The sulfonamide binds as the anion species.

2. Measure the distance between the sulfonamide nitrogen and

   the hydroxy group of threonine (199). This is a hydrogen bond.

3. Measure the distance between the sulfonamide oxygen (the

   closest one) to the backbone NH of threonine (199). This is also

   a hydrogen bond.

4. Measure the distance between the closest sulfonamide oxygen

   to the zinc atom.