Building Blocks of Proteins: We all know that proteins are essential to living organisms. Biochemically speaking, amino acids (short for α-amino carboxylic acid) are a group of organic molecules that are known to be the basic building blocks of proteins.
We know how proteins play crucial roles in almost all biological and physiological processes, and these amino acids are just equally important.
To tell you how important amino acids are, a rough estimate of about 50 to 2000 amino acids typically comprises a protein. While some of them are only used to create proteins, others perform a variety of roles.
Let’s explore on what are the building blocks of proteins in this article.
Table of Contents
- The Discovery of Amino Acids
- Structure of An Amino Acid
- Properties of Amino Acids
- How Are they Joined Together?
- Examples of Amino Acids
- Functions of Amino Acids
The Discovery of Amino Acids
Structure of An Amino Acid
1. Amino Group
- Almost all amino acids, except proline, have a primary amino (NH2) and a carboxylic group attached to, and are distinguished from each other through their central carbon.
2. Carboxyl Group
- The carboxyl group is composed of a carbon atom and two oxygen atoms and is apparently negative having lost its hydrogen atom as a carboxylic acid (-COOH).
3. R Group (Or Side Chain)
- For instance, the smallest and the simplest amino acid glycine has the hydrogen (H) atom as its R group.
Properties of Amino Acids
In addition to the aforementioned structural characteristics, amino acids are also distinct because of their chirality and acid-base behavior. Such properties allow these amino acids to have profound effects on their overall biological activity.
2. Acid-Base Behavior
How Are they Joined Together?
The bond that joins together amino acids to become proteins is called a peptide bond. This bond is an amide bond, which a type of covalent bond that is created by the reaction (nucleophilic addition and elimination) between the amino group of one amino acid and the carboxylic group of another. As a result, one molecule of water is created as a byproduct.
When joined, amino acids form chains called polypeptide (naturally based from the bond that binds them together) chains, which eventually form the protein structure. As such, a single protein can consist of several specific sequences of amino acids.
To know more about how they’re formed, checkout this video.
Examples of Amino Acids
At present, more than 500 amino acids have been found to occur in nature; however, only twenty of them actually participate during translation process and are deemed as essential ones.
As depicted in the figure above, amino acids can be divided into four different groups depending on their R group and overall structure: non-polar, polar, acidic, and basic.
We can observe that most amino acids are hydrophilic (includes polar, acidic, and basic) in nature. Hence, they make an ideal component of globular proteins in solutions.
Functions of Amino Acids
While most of them act as monomers that form larger units called polymers, amino acids can also function on their own. The following are some of these important functions.
1. Production of Bioactive Compounds
3. Precursors of Other Nitrogen-Containing Molecules
In this article, we have learned the building blocks of proteins, various chemical structures of amino acids in general and how that fact controls the shape and eventually dictates the function of the protein. We have also learned that their functions are not only limited to this.
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