Joshua's Fun with Jolecule Blog Post

Joshua Everett
Fun with Jolecule

Antibodies

Antibodies are molecules that search for viruses, bacteria, and other infectious molecules within an organism. These antibodies are commonly circulating in the blood of humans along with examining all objects that they come into contact with. Specifically when an antibody finds a foreign object in the blood, it attaches to the object and fights off any infection the object might bring to the human. This process can only be fulfilled if the object is a virus and an abundance of antibodies attaches to its surface. On the other hand, if the foreign object in the blood is a type of bacteria, the antibody will attach to the bacteria and only act as a marker protein. This marker will alert more powerful defense molecules to fight off the bacteria from causing infection. Antibodies function in direct correlation with the immune system of individuals, for example, without antibodies people would have a weak immune system and would be unable to fight of disease. Without antibodies, there is not a functional immune system in the body, and individuals would be suffering from constant sickness. 

The basic structure of an antibody is simply a molecule that is made of up of several flexible arms that have binding site at the end of each of them. The abundance of arms help ensure that the antibodies are always prepared to fight off any foreign object no matter what the shape consists of. The binding sites of these flexible arms also are able to work symbiotically to be able to attach to viruses and bacterium despite any complications with the shape. Antibodies, however, vary in their properties and distinctions. Some antibodies only have two arms with binding sites, while others may have ten arms with binding sites. Some antibodies even have additional long flexible linkers that are attached from the molecule to the arms with allows some antibodies to have better coverage over the foreign object they are binding to because of the extra length. Various antibodies originate from genes that are recombined in lymphocytes which are the blood cells that create antibodies. The variety of antibodies creates a system in which only certain antibodies are active when different infections are present in the body. Different antibodies have different binding properties which allow for all viruses and bacterium to be fought off with a different antibody. 

Furthermore, all antibodies are composed of four major chains, two long and heavy chains and two short and light chains. Between two of these chains, a heavy and a short chain, there is room for a binding site from a pocket that is formed between them. These long protein chains vary in length and create many loops which allow them to be appropriately called, hypervariable loops. The loops these chains make form these pockets that allow antibodies to attach to foreign molecules that are attacking the body. The other parts of the antibody molecules have many other chains/arms that are connected to a central domain called an antigen (an antibody generator). This formation stays continually uniform with every antibody. In addition, the antibody structure is also on a quaternary level of protein structure because of the many polypeptide chains that are part of an antibody. In Jolecule, the protein structure depicted only shows one immunogloulin. An antibody will have three of immunologists in its structure. A quaternary structure is considered to be any protein that has more that two polypeptide chains in a molecule. An antibody has many chains, two heavy and two light chains and even more when all three immunogloulins are present, which allows an antibody to fit the criteria of a quaternary structure.   

This picture is depicting the overall structure of what an antibody looks like. The immune system forms antibodies that are made up of three major components, light chains, heavy chains, and a central domain, an antigen. All three parts of the antibody work together to be able to fight of foreign particles. 

This picture depicts the top of the binding site where the chains are forming loops in the molecule. In the immune system, antibodies are produced from the mutated residues contributed by the binding site from the loops shown.

This picture depicts a single protein called an immunogloulin. An immunogloulin is only one of the three immunogloulin in a complete antibody. One immunogloulin contains heavy chains, light chains, and an antigen is attached between the chains.  Two immunogloulins act as the Y structure of an antigen and contains a heavy and light chain. A third immunogloulin acts as a base for the antigen because it only contains two heavy chains and not a light chain and a heavy chain. 

This picture depicts the heavy chain of the antibody goes below the antibody into another domain. In this domain, the heavy chain interacts with other proteins.