Abstract
Oxygen is the elixir of life for all aerobic organisms on Earth. It makes up 21% of the air we breathe, but that wasn't always the case. Initially, our planet's atmosphere was full of carbon dioxide, so only primitive anaerobic organisms, which do not need oxygen for living, could survive. But then a miracle happened: cyanobacteria, tiny organisms, began to use the energy of sunlight to assimilate carbon dioxide and water, a process now known as photosynthesis, which produces molecular oxygen from a water molecule as a by-product. The period that followed is known as the Great Oxygen Catastrophe, as the emergence and accumulation of a new two-atom molecule in the atmosphere led to the butterfly effect, an irreversible event that made our planet what it is today [1]. In turn, this event led to the emergence of multicellular life, which can exist and thrive on Earth with the help of oxygen. In addition to respiration, oxygen protects us from the Sun's harsh ultraviolet radiation through the Schumann-Runge absorption and in the 175–205 nm range and creates an ozone layer in the stratosphere that protects us from the softer UV rays of 240 nm.
Oxygen has been the subject of intense research for more than two centuries, ever since the Swedish chemist Scheele first obtained this pure gas by decomposing black magnesia. However, the mechanisms of reactions involving oxygen in living organisms are still not fully understood. It is now known that reactions of oxygen with organic compounds are forbidden by spin, but photosynthesis and respiration are vivid examples of how this prohibition can be overcome. The O2 molecule has two unpaired electrons (spins) on the outer electron shell, whereas almost all organic matter is diamagnetic and has zero spin.
How molecular oxygen overcomes spin prohibition during its activation by enzymes is discussed in this article. Particular attention is paid to understanding reaction mechanisms in living organisms, using photosynthesis and respiration as examples. Furthermore, the topical area of studying the mechanism of the Ribulose-1,5-bisphosphate carboxylase (RuBisCo) is emphasized, which offers the possibility of developing new approaches to increasing cereal yields for farmers.
References
Carter R. Book of the Month: Oxygen: The Molecule that Made the World. Journal of the Royal Society of Medicine. 2003. 96(1): 46–47.
Minaev B.F. Spin effects in reductive activation of O2 by oxydase enzymes. RIKEN Review. 2002. 44(2): 147–149.
Minaev B. The spin of dioxygen as the main factor in pulmonology and respiratory care. Archives of Pulmonology and Respiratory Care. 2022. 8(1): 28–33.
Minaev, B. F. & Panchenko, A. A. Spin-kataliz okysnennia nenasychenykh substrativ mono i dy-oksyhenazamy, vilnymy vid kofatoru. Yak trypletnyi kysen mozhe podolaty spinovu zaboronu [Spin–catalysis of Unsaturated Substrates Oxidation by Cofactor–free Mono– and Di–oxygenases. How Triplet Oxygen Can Overcome Spin Prohibition]. Ukrainskyi zhurnal medytsyny, biolohii ta sportu – Ukrainian Journal of Medicine, Biology and Sports. 2019. 6. 329–343 [in Ukrainian].
Minaev B. Magnetc Torque in Superoxide Ionis the Main Driving Force of Dioxygen Activation in Aerobic Life. Biomedical Journal of Scientific & Technical Research. 2021. 38(4).
Minaev B. F. Singlet-excited dioxygen O2(a1Δg) and organic pollutants in marine waters beneath the Sun. Annals of Marine Science. 2023. 7(1): 025–033.
Klinman J.P. How Do Enzymes Activate Oxygen without Inactivating Themselves? Accounts of Chemical Research. 2007b. 40(5): 325–333.
Walker B.J., VanLoocke A., Bernacchi C.J., & Ort D.R. The costs of photorespiration to food production now and in the future. Annual Review of Plant Biology. 2016. 67(1): 107–129.
Li X., & Siegbahn P. E. M. Alternative mechanisms for O2release and O–O bond formation in the oxygen evolving complex of photosystem II. Physical Chemistry Chemical Physics/PCCP. Physical Chemistry Chemical Physics. 2015. 17(18): 12168–12174.
Paul S., Neese F., & Pantazis D. A. Structural models of the biological oxygen-evolving complex: achievements, insights, and challenges for biomimicry. Green Chemistry. 2017. 19(10): 2309–2325.
Kannappan B., Cummins P. L., &Gready J. E. Mechanism of Oxygenase-Pathway Reactions Catalyzed by Rubisco from Large-Scale Kohn–Sham Density Functional Calculations. The Journal of Physical Chemistry. B. 2019. 123(13): 2833–2843.
Wildman S.G. Along the trail from Fraction I protein to Rubisco (ribulose bisphosphate carboxylase-oxygenase). Photosynthesis Research. 2002. 73: 243–250.
Gready J. E., Kannappan B. Process for Generation of Protein and Uses Thereof (U.S. Patent No. 9,598,688 B2). United States Patent. 2017.
Sage R. F. The evolution of C4 photosynthesis. New Phytologist. 2003. 161(2): 341–370.
Silva P. J. Refining the reaction mechanism of O2towards its co-substrate in cofactor-free dioxygenases. Peer J. 2016. 4: e2805.
Fetzner S. Oxygenases without requirement for cofactors or metal ions. Applied Microbiology and Biotechnology. 2002. 60(3): 243–257.
Lorimer G. H., &Miziorko H. M. Carbamate formation on the .epsilon.-aminogroup of a lysylresidue as the basis for the activation of ribulosebisphosphatecarboxylase by carbondi oxide and magnesium(2+). Biochemistry. 1980. 19(23): 5321–5328.
Andersson I., &Taylor, T. C. Structural framework for catalysis and regulation in ribulose-1,5-bisphosphate carboxylase/oxygenase. Archives of Biochemistry and Biophysics. 2003. 414(2): 130–140.
Andersson I. Catalysis and regulation in Rubisco. Journal of ExperimentalBotany. 2007. 59(7): 1555–1568.
Bathellier C., Yu L.J., Farquhar G.D., Coote M.L., Lorimer G.H., &Tcherkez G. Ribulose 1,5-bisphosphate carboxylase/oxygenaseactivates O2 by electrontransfer. Proceedings of the NationalAcademy of Sciences of the United States of America. 2020. 117(39): 24234–24242.
Minaev B.F., & Valiev R.R. Spin-orbit coupling effects in O2 activation by cofactor-independent 2,4-dioxygenase. The Ukrainian Biochemical Journal. 2019. 91(1): 38–46.