Protein Shapes

There are hundreds, if not thousands, of metabolic processes occurring in each of the trillions of cells in your body at this very moment. Each of those processes requires the work of a team of specialized proteins, and each of those proteins must have a particular shape in order to perform its assigned task.


Examples of Protein Shapes

 If a particular protein fails to achieve the proper shape when it's formed the fitness of the cell will suffer, and thereby hangs an interesting problem. Given that the universe of possible configurations that a protein could adopt is vastly greater than the number of seconds since the earth formed, how is it that natural selection was able to "discover" all of the highly specific shapes of each of the myriad proteins necessary for even the simplest cell to function?

Biologists tell us that the shape of a protein is a function of the sequence of amino acids that make up the protein, much like beads make up a necklace, but how, out of all the possible sequences there are, did just the right sequence arise, not just once but hundreds of times in the first cell?

Cornelius Hunter offers an interesting discussion on the problem at Darwin's God. He writes:

But [the protein] works just fine only because a very special amino acid sequence was specified. That amino acid sequence is just as astronomically rare as the three dimensional structure that the unfolded protein was able to find. So from where did this amino acid sequence come?

The string of amino acids that make up a protein comes from the cell’s translating machine called the ribosome. The ribosome takes as input a string of nucleotides and produces as output a string of amino acids. The translation is done according to the genetic code.

And from where did the string of nucleotides come? It came from the DNA. A massive protein copying machine slides along an opened section of DNA and copies a gene.

And from where did the DNA gene come? According to evolution it evolved, but it is here that we find another entropy barrier. Just as the folding protein is confronted with an astronomical number of possible structures, so too the DNA gene is confronted with its own nightmare of choices.

This is one of the main reasons why explaining the origin of life is such an intractable problem. DNA is a code. It's information. Where did this information come from. Could it have been produced by chance and blind forces, or did it require intention and intelligence?

We've never experienced information such as a code being produced apart from a mind, and yet despite the complete lack of empirical warrant the naturalist takes an enormous leap of faith and chooses to believe, without any evidence, that not only is it possible to have produced a code by chance, but that it actually happened in the origin of living things.

Then the naturalist, having committed himself to the belief that unthinking nature is capable of such miracles - the equivalent of believing that a computer program could be produced by a random symbol generator - criticizes those who are skeptical of such wonders as being superstitious and unscientific for thinking that the existence of information points to the existence of an intelligent mind.

It's actually rather amusing.