Biological complexity: how proteins fit together (Introduction)

by David Turell , Thursday, April 06, 2023, 18:23 (387 days ago) @ David Turell

Parts interlock into each other:

https://phys.org/news/2023-04-role-dating-bacteria-evolution.html

"Proteins are the key players for virtually all molecular processes within the cell. To fulfill their diverse functions, they have to interact with other proteins. Such protein-protein interactions are mediated by highly complementary surfaces, which typically involve many amino acids that are positioned precisely to produce a tight, specific fit between two proteins. However, comparatively little is known about how such interactions are created during evolution.

"Classical evolutionary theory suggests that any new biological feature involving many components (like the amino acids that enable an interaction between proteins) evolves in a stepwise manner. According to this concept, each tiny functional improvement is driven by the power of natural selection because there is some benefit associated with the feature. However, whether protein-protein interactions also always follow this trajectory was not entirely known.

"Using a highly interdisciplinary approach, an international team led by Max Planck researcher Georg Hochberg from the Terrestrial Microbiology in Marburg have now shed new light on this question. Their study provides definitive evidence that highly complementary and biologically relevant protein-protein interactions can evolve entirely by chance.

***

"The Berlin team then tested whether ancient molecules could form an interaction. This way the scientists could retrace how both protein partners got to know each other. "Surprisingly, the FRP from the proteobacteria already matched the ancestral OCP of the cyanobacteria, before gene transfer had even taken place. The mutual compatibility of FRP and OCP has thus evolved completely independently of each other in different species," says Thomas Friedrich.

"This allowed the team to prove that their ability to interact must have been a happy accident: selection could not plausibly have shaped the two proteins' surfaces to enable an interaction if they had never met each other. This finally proved that such interactions can evolve entirely without direct selective pressure.

***

"'This may seem like an extraordinary coincidence," Niklas Steube says. "Imagine an alien spaceship landed on earth and we found that it contained plug-shaped objects that perfectly fit into human-made sockets. But despite the perceived improbability, such coincidences could be relatively common. But in fact, proteins often encounter a large number of new potential interaction partners when localisation or expression patterns change within the cell, or when new proteins enter the cell through horizontal gene transfer."

"Georg Hochberg adds, "Even if only a small fraction of such encounters ends up being productive, fortuitous compatibility may be the basis of a significant fraction of all interactions we see inside cells today. Thus, as in human partnerships, a good evolutionary match could be the result of a chance meeting of two already compatible partners."

Comment: so these folks prove chance interactions can occur in the lab by human interactions. Not by natural selection. Pure Darwinist pipedream. What are the real 'natural chances'? It is trying to save Darwinism from design theory attacks.