Biological complexity: Size of body protein reactions (Introduction)

by David Turell , Wednesday, April 08, 2020, 19:12 (1690 days ago) @ David Turell

Only two to eleven percent of reactions described:

https://phys.org/news/2020-04-world-largest-protein-clues-health.html

"The human body is composed of billions of cells, each of which is made and maintained through countless interactions among its molecular parts. But which interactions sustain health and which ones can cause disease when they go awry? The human genome project has provided us with a "parts list" for the cell, but only if we can understand how these parts go together, or interact, can we really begin to understand how the cell works and what goes wrong in disease.

"To answer these questions, scientists needed a reference map of interactions—an interactome— between gene-encoded proteins, which make up cells and do most of the work in them.

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"Humans have about 20,000 protein-coding genes but scientists still know remarkably little about most of the proteins they encode. Fortunately, this information can be gleaned from interaction data thanks to the "guilt by association" principle, according to which two proteins that have similar interacting partners are likely involved in similar biological processes.

"'We can use our human interactome map to predict protein function," says Roth, who is also Senior Scientist at the Sinai Health System's Lunenfeld-Tanenbaum Research Institute. "People can look up their favourite protein and get clues about its function from the proteins it interacts with."

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"The team tested all possible pairwise combinations among 17,500 proteins for their ability to interact with each other in three separate versions of a yeast-based assay, each done in triplicate, amounting to a staggering three billion separate tests. The results yielded ~53,000 high-confidence binary interactions between more than 8,000 proteins, which were verified by other methods. The majority of interactions had never been detected before.

"Although the largest map of its kind to date, the map remains incomplete, representing between 2-11 per cent of all human protein interactions. Roth said that one reason why many interactions were missed is probably because yeast cells lack certain human-specific molecular factors that are needed for proper protein function."

Comment: this shows how little we know about how life emerges from the mass of protein molecule reactions, all coordinated with each other. Some of the processes are simply maintenance (think producing urine, or oxygen CO2 exchange) At the same time the amounts of protein product produced is under tight controls by feedback loops of molecules. Most protein molecules are quite large, and required enzymes which must be present to speed all biochemical reactions, because they basically cannot otherwise occur/be completed at anywhere near the speed needed. No question design is required. The only debate is what or who is the designer. Any sensible thought realizes it is a mental giant!