Chemical interactions

Interactions between drugs and their target are usually based on a combination of different bond types. These interactions are necessary to form a stable drug-target complex which allows a response.

Four different bond types between two molecules (e.g. the drug and its target):

  • Van der Waals are very weak attractive or repulsive forces. They result from transient positive or negative charges on a molecule caused by the shifting of its electron density.

  • Hydrogen bonding uses the principle that hydrogen atoms bound to nitrogen or oxygen become more positively polarized. This allows these hydrogen atoms to bind to more negatively polarized atoms such as oxygen, nitrogen, or sulphur.
  • Ionic interactions occur between atoms with opposite charges.
  • Covalent bonding is the strongest bond type. The chemical bonding is characterized by the sharing of pairs of electrons between atoms. The energy required to break such a bond is irreversible.

Most drugs work by non-covalent interaction with biomolecules such as proteins or RNA. If a drug binds with covalent bonding to a receptor, it is considered irreversible binding.


Which type of chemical interaction causes proteins to have its tertiairy structure? (Multiple answers possible)