The Problem of Protein Folding

For any natural origin of life model to be credible, it must explain the development of the chemical interactions that transformed dead, inert matter into to living, goal-oriented, reproducing cells containing complex DNA. It's not enough to assume all living species evolved from common processes simply because they share common physical traits. One must show the transition from inert matter to living cells. Otherwise, claims regarding the model can only be based on speculation - not facts as evolutionists like to claim.

To better appreciate the problem consider the problem of protein folding. Proteins are the primary components of cells and execute nearly all cell functions. They supply skeletal structure and muscular growth and movement, they control our senses, they defend against disease and digest food. Examples of the protein types found in the human body:

1. Physiological: controlling such things as sight, smell, and hearing.

2. Structural: controlling the expansion and contraction of muscles and giving elasticity to connective tissues (collagen in bones, cartilages and tissues).

3. Transportive: moving materials such as oxygen (hemoglobin in blood) from the lungs to tissues.

4. Chemical: enzymes function to digest food and catalyze biochemical reactions that control and coordinate cell division. Receptor proteins receive stimulants and initiate responses in cells.

Because of the critical role they play, proteins are the most important molecules in living organisms. Without proteins cells can not live.

So, one question to ask proponents of natural origins is, "How did proteins originate?"

Regarding the composition of proteins, they are composed of amino acids. Human proteins, specifically, are composed of 20 different kinds of amino acids, 10 of which our body can produce by itself (non-essential amino acids) and 10 that must be obtained through food (essential amino acids). The human body contains approximately 100,000 proteins and every one of them are constructed from only 20 amino acids.

Moreover, excess amino acids are not stored like fats and starches so they must be constantly manufactured by the body and obtained from food. Failure to obtain even one of the essential amino acids severely compromises the body's ability to repair itself and sustain life.

Now, here's where things get especially interesting. Amino acids form the structure, or the shape - 3D shapes, actually - of proteins. More precisely, it's the amino acid sequence that determines the shape. The amino acid sequence is determined by the gene sequences in the cell's DNA. The gene sequences provide the code (known as codons) to link amino acids into proteins. More on this in a later post, but for now, suffice it to say that cells contain protein making mechanisms that link amino acids at a rate of almost 300 a minute.

Why so fast? Perhaps the rate is necessary to make the proteins functional. Proteins become functional only when they transform from their linear sequence of amino acid chains into 3-D structures. The process is called protein folding and is not understood by scientists.

In other words, the mechanisms that cause a linear chain of amino acids - that are functionally inert - to fold into 3-D structures - that are functionally active - in fractions of a second, is an issue that must be answered for a credible origin of life theory.

The problem is that protein folding is not explained by chemical reactions. Moreover, why do they form shapes at all? And why is it that only some shapes are beneficial for life and others are destructive? It's believed, for example, that malformed shapes are the cause for diseases like Alzheimer's, Cystic Fibrosis and Parkinson's disease. These questions are not answered by random chance.

In 1969, a scientist, Cyrus Levinthal calculated that a protein consisting of only 100 amino acids could theoretically form into as many as 10^30 possible shapes - that's 1 followed by 30 zeros. Even if a protein could change shapes 100 billion times per second, it take 100 billion years to try all the possibilities - longer than the Universe's age. Imagine the improbability of the largest protein, Titin, which consists of almost 27,000 amino acids!

Because of these issues, many scientists believe that discovering and explaining protein folding is the most important task in biochemistry.

Indeed, from my perspective, the complexities of the celluar mechanisms involved and the unlikeliness that proteins form beneficial shapes lead me to believe they originated from a Designer.

For additional information, see: The Importance of Protein Folding.