Year: 2022

RUBISCO CONTENDER. "The Rubisco protein...is responsible for atmospheric carbon fixation, literally building the biosphere out of thin air. This molecule, one of the most abundant proteins on Earth, is responsible for extracting about a hundred Gigatons of carbon from the atmosphere each year. This is ≈10 times more than all the carbon dioxide emissions made by humanity from car tailpipes, jet engines, power plants and all of our other fossil-fuel-driven technologies." http://book.bionumbers.org/how-big-is-the-average-protein/ View in LinkedIn

TOTAL PROTEINS ON EARTH. "The protein universe, the totality of all proteins in all organisms on earth, is vast. Taking the estimated 13.6 million species of living organisms on Earth, which is very likely to be an underestimate, into account, there are >10(10) to 10(12) different proteins in all organisms from the three domains of life (Eukarya, Bacteria, and Archaea) on Earth. However, this vast number of proteins are predicted to consist of only ≈10(5) sequence domain families, the members of each family having similar amino acid sequences." https://lnkd.in/eNZCgi2 View in LinkedIn

QUESTION: "How has the total number of proteins on Earth changed over the last few billion years, and how will it change in the future?" https://lnkd.in/e25WaJr View in LinkedIn

ANSWER: "It's fairly safe to assume that biodiversity can serve as a reliable proxy for protein levels, since abiotic processes that produce proteins are very rare (only happens in submarine hydrothermal vents, if anywhere). If the assumption holds, then the number of proteins has been increasing since the appearance of life 4 - 3.9 billion years ago, experiencing a huge jump 2.3 - 2 Ga with the development of photosynthesis and in the Great Oxidation Event, both of which led directly to an increase in the complexity of life." https://lnkd.in/e25WaJr View in LinkedIn

ASSUMPTIONS. "Two assumptions are generally made when considering the molecular evolution of functional proteins during the history of life on Earth. Firstly, the size of protein sequence space, i.e., the number of possible amino acid sequences, is astronomically large and, secondly, that only an infinitesimally small portion has been explored during the course of life on Earth." https://lnkd.in/eyPrQUq View in LinkedIn

"PROTEIN SEQUENCE SPACE is often viewed as a limitless desert of maladjusted sequences with only a few oases of working sequences linked by narrow pathways. The navigation over this space by natural selection is difficult and could take many different routes thus resulting in organisms with largely different protein compositions." https://lnkd.in/eyPrQUq View in LinkedIn

VAST NUMBERS. "A typical estimate of the size of sequence space is 20(100) (approx. 10(130)) for a protein of 100 amino acids in which any of the normally occurring 20 amino acids can be found. This number is indeed gigantic but it is likely to be a significant overestimate of the size of protein sequence space." https://lnkd.in/eyPrQUq View in LinkedIn

COMPLEXITY FROM SIMPLICITY. "The conclusion from all of these coarse-graining approaches is that a reduced alphabet of amino acids is quite capable of producing all protein folds (approx. a few thousand discrete folds) and providing a scaffold capable of supporting all protein functions." https://lnkd.in/eyPrQUq View in LinkedIn

2ND ASSUMPTION. "Considering the upper limit, it is clear that bacteria dominate the planet in terms of the product of the number of cells (10(30)) multiplied by the number of genes in each genome (10(4), a small overestimate)." https://lnkd.in/eyPrQUq View in LinkedIn

2ND ASSUMPTION. "Let us assume that every single gene in this total of 10(34) is unique and that evolution has been working on these genes for 4 Gyr completely changing each gene to some other unique, new gene every single year. This gives an extreme upper limit of 4×10(43) different amino acid sequences explored since the origin of life." https://lnkd.in/eyPrQUq View in LinkedIn