Thursday, November 19, 2015

Wonders of Proteins

Our bio-science vocabulary is expanding. Within the lifetimes of today’s senior citizens, the molecule of DNA was named as the bearer of genetic information. By mid 20th century, brilliant discoveries about the structure of the DNA molecule were published. Soon the DNA genetic code was discovered. Inherent in DNA was a code for producing the proteins composing the bodies of living things. This century the complete human genome has been published: The term genome means the complete genetic information necessary to produce proteins composing the human body. From this information comes the knowledge of genomics. The complete human genome became available in 2003—three billion bits of coded genetic information. Genomics has been a well-known term in our bio-science vocabulary since 1986.

Knowledge of the human genome enables bio-scientists to catalog the thousands of proteins, structural building blocks of the human body. Proteins enable many other body functions. They are complex molecules formed from chains of molecules of twenty different amino acids assembled in innumerable ways. Human bodies consist of 50,000 different proteins. Millions of other species on earth are composed of many millions of different protein molecules. Proteins are chemical combinations of the elements carbon, hydrogen, oxygen, and nitrogen. The raw materials are simple, but the possibilities for their combination are virtually limitless.

It is time to introduce another vocabulary term—proteomics—a study of the structure and function of the entire set of proteins known. The term was introduced to the science community in 1997. We easily see that as our knowledge of the wonders of life forms grows, our bio-science vocabulary grows with it. With our understanding of the DNA blueprint of protein coding (genomics) fairly complete, we now turn to an issue related to the more recently discovered discipline of proteomics. How do we continue to understand the structure and function of proteins? First, we turn to the structure of proteins. We discover that form of the multiple thousands of protein molecules is related to their function. 

The principle of “form fits function” is vitally important in bioscience. Molecules, cells, tissues, organs, and complete organisms operate by the reality of “form fits function.” This principle may be initially difficult for beginning students to grasp. Therefore, without being overly pedantic, I may search for a mundane classroom example before continuing with lessons on what happens to proteins after they are produced in body cells as linear chains of amino acids.

Students have heard of the Japanese art of origami, the science of paper folding. Flat, square sheets of paper may be folded and formed into various shapes limited only by the creativity of the folder. Many thousands of forms are possible. Do we wish to create an origami airplane? The product shape (form) lends itself to its intended function—flying. Unfolded origami paper is shaped simply, usually in square sheets. The paper is composed of a few simple, basic elements. The final product, however, may manifest virtually limitless shapes and serve many purposes.  

One inquirer requested examples of “form fits function” in the world of biology on a well known question and answer website. The responder cited two: Blood cells and sharks’ teeth. Each has specific forms fitting special functions. Likewise, protein molecules which are initially produced as simple linear chains of molecules of amino acids inside the cell must fold into the correct, three-dimensional shape in accordance with their ultimate function in the body.

Specialists in proteomics have explained the protein folding process with some success. They explain what happens with respect to protein function better than how and why it happens.” We know, however, that complete knowledge of the protein folding phenomenon is in the purview of the Creator of all life forms.