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Secondary Structure of Protein

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An Overview of the Secondary Structure of Protein

Before understanding how the proteins are classified on the basis of the secondary structure of protein, it is essential to know why proteins are so important. Nearly every single function in the organisms is a result of the proteins. These components account for about 50% of the entire cell mass and have a pivotal role to play in every single process of the body. 

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There are different types of proteins that play different roles in speeding up the chemical reactions, providing defense, storage, movement of cells and communication, and structural support in organisms. Human beings have thousands of different proteins existing in their bodies at any particular time. Every single one of these proteins has its very own function and structure.

Classifying Proteins According to the Secondary Structure

Every protein has its description from the structure that it has. These structures are primary structure, secondary structure, tertiary structure, and quaternary structure. To explain it in brief, the primary structure focuses on the linear chains consisting of amino acids. 

The secondary structure consists of different regions stabilized due to the presence of hydrogen bonds. The tertiary structure represents the 3-D protein shape determined by all the stabilized regions due to the interactions of side chains. The Quaternary structure is an association created by polypeptides. In this article, students will get to focus on the secondary structure of protein example.

What is the Secondary Structure of a Protein? 

The secondary structure of protein refers to the three-dimensional form associated with the local segments that are present in proteins. The two common elements in the classification of the secondary structure of protein include beta-sheets and alpha-helices. Although beta turns and omega loops are occurrences of the secondary structure too, they are not very common. The elements of secondary structure are spontaneously formed as a type of intermediate before the protein is folded into the three-dimensional structure. 

The hydrogen bonds formed in the secondary structure between the carboxyl oxygen and amino hydrogen atoms help describe the structure perfectly. These bonds occur on the backbone of the polypeptides. The secondary structure might be alternatively defined on the basis of some regular patterns seen in the backbone dihedral angles. 

This secondary structure of protein diagram will help explain the topic in detail.

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Difference Between Primary and Secondary Structure of Protein

Here is the difference between primary and secondary structure of protein.

Primary Structure

Secondary Structure

The Primary structure tends to have a linear form.

The secondary structure can assume the form of alpha helices or beta-sheets.

The primary structure is formed during the process of translation.

The secondary structure acts in the creation of collagen, actin, myosin, elastin, and other keratin-type fibers.

The main involvement of the primary structures is in the post-translational processes.

The main involvement of the secondary structures is in the creation of structures that include ligaments and cartilages amongst many others.

The primary structure of the proteins is the exact ordering of certain amino acids that form the chains. It is really important to determine the exact sequence in these proteins due to the fact that it helps in determining the final fold. Therefore, it decides the protein’s functions.

In the case of the secondary structure, the proteins don’t exist in particular simple chains consisting of polypeptides.

The different numbers of polypeptide chains group together to result in the formation of proteins following the primary structure. These chains tend to have certain amino acids that are properly arranged in a proper sequence and hence provides the protein with its characteristics. Any changes in the sequence will result in the changing of the protein.

These chains are folded and the reason behind that is the interaction that takes place between the carboxyl and the amine group in the peptide link. In the case of this particular structure, the main reference is to the shape that is created for the elongated polypeptide chain to exist.

There are two different structures included in the secondary structure. Alpha helix and beta-pleated sheets are the most commonly occurring elements. Since the polypeptide chain backbone is constantly folding due to the presence of hydrogen bonding, the structure is created. There are certain segments belonging to the chain of proteins that might have their very own fold locally. This enables the structure to become much simpler. Such local folds are named secondary elements and result in the formation of the secondary structure of proteins.


The secondary structure of protein takes the next level upwards from the protein’s primary structure. It is also the regular folding of different regions into certain specific structural patterns that exist within a single polypeptide chain. The secondary structures’ primary function is to hold the hydrogen bonds together that are created between the amide hydrogen and the carbonyl oxygen in the peptide bonds.

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FAQs on Secondary Structure of Protein

1. What is the secondary structure of a protein? 

In a general sense, there are four levels when it comes to deciding the structure of the proteins. There is the primary level, secondary level, tertiary, and quaternary level of the structure. There are different purposes and roles for every single one of the protein structures. In the case of secondary structures, the main idea is for the creation of the three-dimensional form of the proteins. Some common elements of the secondary structure of protein include the alpha helices and the beta-sheets. The secondary structure is formed due to the creation of different hydrogen bonds between the carbonyl oxygen compound and the amide hydrogen compound present.

2. Describe the process of protein formation and protein folding. 

The amino acids are responsible for the creation of a polypeptide, which is another name given to denote the protein. These amino acids are bound by a particular sequence consisting of different peptide bonds which lead to the creation of proteins. Then the polypeptides will fold in order to form a certain conformation on the basis of the interactions that happen between the side chains in the amino acids. The process of protein folding can be defined as the mechanism through which the protein structure is able to assume the functional shape that it has. The molecules present in the proteins are both heterogeneous and unbranched amino acids. Hence, they perform their function by folding and coiling to create a three-dimensional structure.