Monday, October 14, 2019

The Functional Advantages of Protein Oligomerization

Evolution Creates Evolution

As I have discussed many times, a single, run-of-the-mill, protein is beyond evolutionary explanation. The fitness landscape in protein sequence space is typically rugged, with occasional spikes representing protein designs. The resources required to evolve even a relatively simple protein exceed what evolution has available by at least 27 orders of magnitude. And that is generous as it comes from studies done by evolutionists. But proteins cause many more problems for evolution beyond their initial origin. For instance, something like a third of proteins form oligomers—protein machines consisting multiple subunits that bind together. Hemoglobin, for example, consists of four units, two alpha chains and two beta chains. Each chain is roughly 140 amino acids long. Michael Behe showed in his book The Edge of Evolution that the origin of simply the oligomeric interfaces is beyond evolutionary explanation. But again, the problems do not stop there. Even if evolution could somehow oligomerize proteins, what would happen then?

Oligomers may be homogeneous, consisting of repeats of the same subunit, or they may be heterogeneous, consisting of different subunits. Either way, it is unlikely that if evolution were somehow get lucky and not only construct proteins, but oligomerize them, that some great new function would arise. If so, it would represent a great amount of serendipity, for the new function would have been a lucky result. Imagine combining a few shovels to get a windmill.

But if there was no new function, then what would be the value of the new oligomer? The problem is not that evolutionists have no idea, but rather that they have too many ideas, none of which make sense. Here are six potential functional advantages that oligomerization may confer, as summarized in a review paper:

(1) More complex scaffolds may better support function, for example, by the introduction of a new active site at the interface between subunits. It has been estimated that roughly one sixth of oligomeric enzymes has an active site located at the inter-subunit interface.
(2) Oligomeric proteins can be allosterically regulated, introducing an additional level of control.
(3) There is a greater likelihood of an error-free transcript in a shorter protein sequence. A large protein composed of multiple, short, subunits, is more likely to be synthesized without errors than a single chain protein of comparable size.
(4) Where the monomer and oligomer differ in activity, additional regulatory flexibility may be achieved by regulating the conditions of oligomerization.
(5) Oligomeric proteins may be subjected to amplified evolutionary pressures, as deleterious mutations may be more pronounced and thus removed sooner from the gene pool. Conversely, the advantages of beneficial mutations may also be made evident sooner.
(6) Larger proteins are more resistant to degradation and denaturation. Indeed, an increase in oligomerization state is one of the protein stabilization strategies observed in thermophilic organisms.

Evolutionists are deeply wedded to teleological thinking. They have also constructed a theory full of serendipity. This summary is an example of both these trends, which often go together.

These six functional advantages imagined by evolutionists do not represent immediate improvements. For example, the second entry states that “oligomeric proteins can be allosterically regulated, introducing an additional level of control.” But immediately upon oligomerization, there would be no such regulation.

In fact, that is a generous understatement. For the evolution of allosteric regulation is far beyond evolution’s resources. The point here is that these imagined functional advantages of oligomerization call for an enormous helping of serendipity. Evolution creates X, which then enables some later evolutionary step to be taken. In this case, oligomerization is supposed to have assisted in the evolution of allosteric regulation.

Or again, the fifth entry states that “oligomeric proteins may be subjected to amplified evolutionary pressures.” Forget about the possible instabilities this could introduce, it apparently makes for a superior evolutionary process. So again, we have evolution constructing X, which then makes for better evolution. In short, evolution creates evolution.

Religion drives science, and it matters.

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