# What are the primary/secondary/tertiary structures of proteins?

Sep 5, 2015

primary is the polypeptide sequence of the protein.
secondary structure forms due to Hydrogen bonding they are local structure
tertiary structure are the three dimensional packaging of protein

#### Explanation:

primary structure is a polypeptide sequence translated from the mRNA of the Gene coding the proteins. Polypeptide chains contain various amino acids from the pool of 20 amino acids.

Secondary structure is the packaging of the polypeptide chain into a complex packaging through formation of Hydrogen bonds between various amino acids, amino and carboxylic groups in the chain. these hydrogen bonding result in formation of $\alpha$-helix $\beta$ sheet

Tertiary structure is 3D packaging of the protein which is one step more complex than the secondary structure and have active site for most of the protein. Tertiary structure is really the form in which most of the proteins shows activity.

There is quartenary structure also present which is formed when many tertiary structure comes together to form one functional complex.

Following image better explains what are primary (polypetide sequence), secondary(local Hydrogen bonds resulting in $\alpha$-helix $\beta$ sheet) and tertiary structure (3D structure of the protein) .