Explain briefly four levels of protein structure?
The four levels of protein structures are explained below: Primary Structure: A protein occurs as a long chain of amino acids organized in a certain sequence. For example, the polypeptide is non-functional. Secondary Structure: The first amino acid is known as N-terminal amino acid, while the last is known as C-terminal amino acid. Every fourth amino acid interacts with another by forming a hydrogen bond, and the polypeptide is folded in a helical shape, as in keratin. When two or more polypeptide chains are joined together by intermolecular hydrogen bonds, a pleated sheet structure is formed. Tertiary Structure: The polypeptide is stabilized by folding and coating, which results in the creation of ionic bonds, hydrophobic bonds, or disulfide bridges. It is referred to as a tertiary structure. It displays proteins in three dimensions. The biological activity of a protein is determined by its tertiary structure. Quaternary Structure: These proteins are made up of several polypeptides or subunits, each with its primary, secondary, and tertiary structure. This is referred to as a quaternary structure. Each polypeptide chain serves as a protein component
