Would someone give me the examples of secondary, tertiary and quaternary structures of proteins?
Answers
Secondary Structure:
This structure of a protein involves the folding of regions within one polypeptide chain giving it a specific structural pattern interconnected by peptide bonds and other molecular interactions introduced by the amine and carboxyl groups of the polypeptide chain. Alpha-helix and beta-pleated sheet structures are examples of two different types of secondary protein structures. Alpha-helix is a secondary structure that is formed by the interaction of hydrogen bonds with the amine group to the carboxyl group of adjacent amino acids. Therefore, this forms a twisted structure of polypeptide chains. Beta-pleated sheet is a secondary structure that is held by the intermolecular forces of hydrogen bonding. The polypeptides in this structure are bonded yet stretched-out to one another and form a fold of pleated drapes.
Tertiary Structure:
This structure of a protein involves the formation of a three-dimensional structured arrangement of regions of all amino acids in a polypeptide chain. The conformation, native, and active folding of tertiary proteins are constructed and bound together by multiple molecular interactions such as electrostatic forces, disulfide bonding, hydrogen bonding, and Vander Waals force in bringing stability to the protein structure. Fibrous and globular proteins are examples of tertiary protein structures. Fibrous proteins are long and narrow and are characterized to have repetitive amino acid sequences that provide structural support to the organism. On the other hand, globular proteins are round and spherical proteins that mainly provide functional support to the cells and are characterized to have various amino acid types in their sequence chain.
Quaternary Structure:
This structure of protein consists of the spatial arrangement of multiple noncovalent interactions of two or more polypeptide chains of proteins from the tertiary level of protein structure. Parts of the quaternary protein structure having their specific three-dimensional conformation are called domains where other biomolecules interact aside from other proteins.