Welcome to the Anatomy of Proteins

Welcome to my blog about Biology. My name is Asel Kuanyshbek and currently, I am studying in Nazarbayev University, Astana, Kazakhstan as a first year Biology student. I think that Biology is very interesting and through it, new things can be discovered every day. That is why I picked Biology as my major. In this post, I will be explaining a topic that we have recently passed in Modern Biology 1. Macromolecules: Proteins. Specifically, their structure.

Macromolecules

First of all, we need to know what macromolecules are.
Macromolecules are large organic molecules made up of a number of repeating units called monomers. Monomers join together by condensation reaction, when H2O is released, to make a polymer = macromolecule.[1] For more information on macromolecules you can visit this site.

Protein Monomers

So, how are proteins related to macromolecules?

According to HHMI-Missouri, proteins are a macromolecule itself. They consist of one or more chains of amino acids and they play a vital role in our organism. All amino acids have a similar basic structure and the R side chain gives the amino acid its specific properties. When amino acids are joined to make proteins a peptide bond is formed between amino acids.

Source: http://education-portal.com/cimages/multimages/16/amino_acid_structure.png

As I previously stated, amino acids are binded together by peptide bonds to form proteins, but you may not have know that proteins have 4 different structures. (formations)

Structure[2]

The first structure is the primary structure. It consists of a sequence (chain) of amino acids and is usually called the polypeptide backbone.

The secondary structure also consists of a sequence of amino acids. However, this time, the primary structure coils or folds to produce either an alpha helix or a beta sheet. The alpha helix results from hydrogen bonding of neighboring peptide bonds. While, the beta sheets result from hydrogen bonding between peptide bonds of different strands of the same polypeptide backbone.
So this is how they look like:

Source: https://biochemanics.files.wordpress.com/2013/04/secondary.png

The tertiary structure is made when the secondary structure of a protein is folded and twisted into a round three-dimensional shape. Globular proteins such as enzymes usually have a tertiary structure.

Not many proteins have a quaternary structure. This is because a quaternary structure requires more than 1 polypeptide (chain of amino acids). Hemoglobin is an example of a quaternary protein.

This is how all the structures look like:

Source: http://cnx.org/resources/dd07e14d3e27fe2a7ef27c417bab74ec/Figure_03_04_09.jpg

Structural Mutations

Proteins have optimal temperatures and pH levels that have to be constant for them to work. If the temperature is too high or the pH is not for the protein, then it starts to denature. To denature is to lose shape and bonds. This is very critical as the structure of the protein unfolds and the protein becomes useless or mutates into a different protein, which can lead to neurodegenerative diseases. Fortunately, these "mutated" proteins are taken by chaperones, which assist in protein folding, to a destructive structure called the proteosome.[3]

Thank you for reading until the end. Please leave a comment below. If you would like to find out about proteins in general you can visit this site.

Resources:

"Macromolecules." HHMI-Missouri. http://hhmi.missouri.edu/assets/docs/prep/Macromolecules.pdf (accessed September 30, 2014).

Kimball. "Proteins." Proteins. http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/P/Proteins.html (accessed September 30, 2014).

"The Rules of Protein Structure." Rules of Protein Structure. http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/D/DenaturingProtein.html (accessed September 29, 2014).

"The Structure of Proteins." The Structure of Proteins. http://www.vivo.colostate.edu/hbooks/genetics/biotech/basics/prostruct.html (accessed September 28, 2014).