The tertiary structure of a protein represents its overall three-dimensional shape, which arises from the twisting and bending of a peptide chain. This structure is stabilized by interactions between the side chains, or R groups, of the amino acids, involving both close and distant R groups. Understanding the journey to a fully functional protein begins with the primary structure, which consists of amino acids linked together by peptide bonds. This is followed by the secondary structure, which can manifest as alpha helices or beta-pleated sheets.
In the tertiary structure, the polypeptide chain continues to fold, incorporating both alpha helices and beta-pleated sheets, leading to a more complex and functional form. It is important to note that the formation of the tertiary structure does not alter the primary and secondary structures; rather, it builds upon them. The primary structure may contain segments that form alpha helices and beta-pleated sheets, and as the chain folds into its tertiary structure, it retains these elements while achieving a more intricate configuration.
This process is crucial for the protein's functionality, as the specific three-dimensional shape determines how the protein interacts with other molecules. Thus, the progression from primary to secondary to tertiary structure is essential in the development of a fully functional protein, emphasizing that each structural level contributes to the final form without negating the previous stages.