Biochemistry & Pharmacology: Open Access
Open Access

Protein-folding

Protein folding is a process by which a polypeptide chain folds to become a biologically active protein in its native 3D structure. Protein structure is crucial to its function. Folded proteins are held together by various molecular interactions. During translation, each protein is synthesized as a linear chain of amino acids or a random coil which does not have a stable 3D structure. The amino acids in the chain eventually interact with each other to form a well-defined, folded protein. The amino acid sequence of a protein determines its 3D structure. Folding of proteins into their correct native structure is key to their function. Failure to fold properly produces inactive or toxic proteins that malfunction and cause a number of diseases. Protein folding is a very sensitive process that is influenced by several external factors including electric and magnetic fields, temperature, pH, chemicals, space limitation and molecular crowding. These factors influence the ability of proteins to fold into their correct functional forms. Extreme temperatures affect the stability of proteins and cause them to unfold or denature. Similarly, extreme pH, mechanical forces and chemical denaturants can denature proteins. During denaturation, proteins lose their tertiary and secondary structures and become a random coil. Although denaturation is not always reversible, some proteins can re-fold under certain conditions.