6.1
Activities of most proteins depend on their interactions with other molecules or ions, known as ligands. Although ligands are able to bind to proteins, not every ligand binds to every protein.
Instead, a ligand binds only to a specific region on a protein’s surface called the binding site. But how do ligand binding sites ensure selectivity when proteins sit in a mixed ligand soup?
The particular arrangement of amino acids in a protein forms a complementary binding site on its surface for a specific ligand. However, complementary shapes are not enough for ligand binding.
Chemical interactions hold the ligand and the protein together. Generally, these interactions are non-covalent, reversible, and weak. Therefore, many of these interactions need to occur simultaneously during ligand binding.
For example, the larger the surface area of interaction, the more Van der Waals interactions can happen. These forces work best for large ligands. For others, the specific conformation of the binding site enables hydrogen bonding or electrostatic interactions.
But if the ligand binding site can form hydrogen bonds, why doesn’t it form hydrogen bonds with the water in its surroundings? The an
Proteins are dynamic macromolecules that carry out a wide variety of essential processes; however, the activities of most proteins depend on their int…
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