As I have said before in these blogs and in my popular book, Unintelligent Design: Refuting the Intelligent Design Hoax, if only they understood the subject, creationists should be acutely embarrassed by a ubiquitous enzyme known by the common name, RuBisCo, which stands for ribulose-1,5-bisphosphate carboxylase/oxygenase.
RuBisCo is probably the least efficient of all enzymes - which is why it is so abundant in nature, accounting for the green we see where photosynthesising plants are growing. It's what gives the planet its characteristic green colour everywhere, apart from the deserts, oceans, polar ice caps and mountain peaks.
It is the enzyme responsible for 'fixing' the carbon in carbon dioxide in the atmosphere, so it can be built up into glucose in photosynthesis. Glucose is the basic sugar from which most other carbohydrates are built and the source of energy on which almost all living organisms ultimately depend. It is also the building block of structural material such as cellulose and lignin for plants and chitin for the exoskeletons of arthropods.
In fact, RuBisCo is so inefficient that it would be a major breakthrough in agriculture if scientists could make it more efficient so more food could be produced with the same resources. An added bonus would be that more CO2 would be extracted from the atmosphere, so reducing global warming.
Imagine that! Something creationists believe was intelligently designed by an omniscient, omnipotent designer that is so badly designed that mere humans are having to redesign it to make it more efficient!
The problem with RuBisCo is its slowness and the fact that it makes frequent mistakes and tried to fix oxygen instead of carbon dioxide which results in a toxic by-product which wastes energy and makes the process even less efficient.
RuBisCo is incredibly bad at doing what it does; only carrying out about three reactions a second against tens of thousands of reactions a second for some enzymes. And it makes lots of mistakes. It finds it difficult to tell oxygen molecules (O2) from CO2and often incorporates it by mistake, causing a chain reaction which causes a loss of carbon and wastes energy. To make matters worse, RuBisCo can end up making xylulose-1,5-bisphosphate which actually inhibits it! [51] Some plants have evolved mechanisms for reducing these mistakes – normally by keeping O2 out of the way – but they appear to have evolved several times, independently and none of them are especially successful.
The origin of this problem is that RuBisCo itself evolved in an oxygen–free atmosphere, so the potential to make this mistake was not a factor natural selection could take into account. Unlike the way an intelligent, omniscient designer would work, natural selection acts on what is, and the here and now, not on what might happen later. Evolution can’t pop into the future and see how things turn out and it has no reverse gear. But an omniscient, omnipotent designer would know in advance how things were going to turn out. And if it did make a mistake an intelligent designer would be capable of scrapping the design and starting again.
No omniscient, intelligent designer would blunder blindly into a problem of its own making and then find itself stuck with the problem, unable to go back and start gain and having to make do with massive inefficiency and massive waste.
Having started off down the road to photosynthesis and having given evolving life forms such a tremendous advantage, despite the inefficiency, there was no going back. Any tendency to change it would result in something even worse, so living things have to make do with what they have got. No planning; no ability to go in reverse, and no one to stand back and think of a better way, and start again. The fact that several plants have evolved different ways to compensate for RuBisCo's inefficiency shows that it not ideal for purpose. No omnipotent intelligent designer would come up with something which has to be compensated for.
On its own, RuBisCo, more than any other phenomenon in the natural world, dispels any notion of intelligent design.
What we now have is a world where masses of energy and resource have to be devoted to overcome the inefficiency of RuBisCo at producing something on which almost every living thing depends, because evolution headed down a route from which it could not turn back.
Just as we would expect, we also have massive needless complexity just to achieve the chemical reactions needed to convert inorganic molecules into a simple six–carbon sugar.
The team's findings were published recently, open access, in the journal Science Advances.
Incidentally, creationists might like to note that this construction of the evolutionary tree of Solanacea RuBisCo is based entirely on acceptance of the TOE as the explanation for why RuBisCo is as is today. Its evolution was driven by environmental changes, especially in levels of atmospheric CCO2. Certainly no sign of a theory in crisis there, then!
It might be surprising that ancient, ancestral RuBisCo might be more efficient today than one which is the product of 20-30 million years of evolution, until one considers that the rise in CCO2 levels only began a few tens of years ago and RuBisCo is the unplanned result of fluctuating environmental conditions which could have made it more efficient in some previous era, but not in this one.
And, of course, the team have been able to strip out lots of evolved redundancy and junk DNA in the process.
The Cornel Chronicle explains:
The authors developed a computational technique to predict favorable gene sequences that make Rubisco, a key plant enzyme for photosynthesis. The technique allowed the scientists to identify promising candidate enzymes that could be engineered into modern crops and, ultimately, make photosynthesis more efficient and increase crop yields.In the abstract to their paper in Science Advances the authors say:
Their method relied on evolutionary history, where the researchers predicted Rubisco genes from 20-30 million years ago, when Earth’s carbon dioxide (CO2) levels were higher than they are today and the Rubisco enzymes in plants were adapted to those levels.
By resurrecting ancient Rubisco, early results show promise for developing faster, more efficient Rubisco enzymes to incorporate into crops and help them adapt to hot, dry future conditions, as human activities are increasing heat-trapping CO2 gas concentrations in Earth’s atmosphere.
The study describes predictions of 98 Rubisco enzymes at key moments in the evolutionary history of plants in the Solanaceae family, which include tomato, pepper, potato, eggplant and tobacco. Researchers use tobacco as the experimental model for their studies of Rubisco.We were able to identify predicted ancestral enzymes that do have superior qualities compared to current-day enzymes.
By getting a lot of [genetic] sequences of Rubisco in existing plants, a phylogenetic tree could be constructed to figure out which Rubiscos likely existed 20 to 30 million years ago
Professor Maureen Hanson, Senior author
Liberty Hyde Bailey Professor of Plant Molecular Biology
College of Agriculture and Life Sciences
Cornell University, Ithaca, NY, USA
Scientists have known that they can increase crop yields by accelerating photosynthesis, where plants convert CO2, water and light into oxygen and sugars that plants use for energy and for building new tissues.
For many years, researchers have focused on Rubisco, a slow enzyme that pulls (or fixes) carbon from CO2 to create sugars. Aside from being slow, Rubisco also sometimes catalyzes a reaction with oxygen in the air; by so doing, it creates a toxic byproduct, wastes energy and makes photosynthesis inefficient.
[…]
In this study, Lin reconstructed a phylogeny – a tree-like diagram showing evolutionary relatedness among groups of organisms – of Rubisco, using Solanaceae plants.
The advantage of identifying potential ancient Rubisco sequences is that carbon dioxide levels were possibly as high as 500 to 800 parts per million (ppm) in the atmosphere 25 million to 50 million years ago. Today, heat-trapping CO2 levels are rising sharply due to many human activities, with current measurements at around 420 ppm, after staying relatively constant under 300 ppm for hundreds of millennia until the 1950s.
AbstractJust as an intelligent designer should have been capable of doing, in order to improve RuBisCo for the modern environment, the scientists have had to go back to an earlier version from a time when the conditions were more like they are today. This is what we get with real intelligent design, unlike what we get with evolution by natural selection.
Plants and photosynthetic organisms have a remarkably inefficient enzyme named Rubisco that fixes atmospheric CO2 into organic compounds. Understanding how Rubisco has evolved in response to past climate change is important for attempts to adjust plants to future conditions. In this study, we developed a computational workflow to assemble de novo both large and small subunits of Rubisco enzymes from transcriptomics data. Next, we predicted sequences for ancestral Rubiscos of the (nightshade) family Solanaceae and characterized their kinetics after coexpressing them in Escherichia coli. Predicted ancestors of C3 Rubiscos were identified that have superior kinetics and excellent potential to help plants adapt to anthropogenic climate change. Our findings also advance understanding of the evolution of Rubisco’s catalytic traits.
Lin, Myat T.; Salihovic, Heidi; Clark, Frances K.; Hanson, Maureen R.(2022)
Improving the efficiency of Rubisco by resurrecting its ancestors in the family Solanaceae
Science Advances; 8(15); eabm6871; DOI: 10.1126/sciadv.abm6871
Copyright: © 2022 The authors. Published by American Association for the Advancement of Science.
Open access
Reprinted under a Creative Commons Attribution-NonCommercial 4.0 International license (CC BY-NC 4.0)
Perhaps a creationist would like to offer an explanation for why their putative omniscient, omnipotent creator has not been able to achieve what human scientists are achieving and why what it managed to achieve is not fit for purpose.
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