What Are the Building Blocks of Proteins?

Proteins are essential components of all living cells and are responsible for a variety of biological functions. They are composed of smaller subunits called amino acids, which are held together by covalent bonds. In this article, we will explore the building blocks of proteins and learn more about their structure and function.

Introduction to Amino Acids

Amino acids are organic molecules that contain both a carboxyl group and an amine group. There are 20 common amino acids which can be incorporated into proteins. Each of these amino acids has a specific carbon skeleton which is referred to as the alpha-carbon. The alpha-carbon is bonded to four other atoms or groups of atoms, including the carboxyl, amine, and two side chains which are known as the R-groups. Depending on the type of side chain that the amino acid contains, it is classified as polar, non-polar, acidic, or basic. The combinations of side chains make protein formation possible, as these interactions play a major role in the folding of the protein.

Formation of the Peptide Bond

Proteins are long chains of amino acids held together by peptide bonds. Peptide bonds are formed when the carboxyl group of one amino acid reacts with the amine group of another. This reaction releases a molecule of water and leads to the formation of an amide bond. The two amino acids are then held together by this amide bond, forming a dipeptide. As the protein continues to grow in size, peptide bonds are formed between the other amino acids in the chain. The number of amino acids present in a protein can range from a few to several thousand.

Primary and Secondary Structure of Proteins

The primary structure of a protein is determined by the sequence of amino acids. This sequence of amino acids forms the backbone of the protein, and dictates its overall shape. Secondary structure is determined by the specific three-dimensional interactions that occur between the amino acids and is dependent upon the R-groups of each amino acid. Common types of secondary structure include alpha helices, beta sheets, and loop regions. These structures further determine the shape and ultimately, the function of the protein.

Conclusion

In conclusion, proteins are essential components of all living cells and are responsible for a variety of biological functions. Proteins are composed of smaller subunits called amino acids, which are held together by covalent bonds known as peptide bonds. Furthermore, amino acids have distinct side chain structures which enable the interaction of different amino acids and the formation of complex secondary structures, leading to the proper folding of proteins. This article provides an overview of the building blocks of proteins and their structural and functional roles in life processes.