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GOOD ENOUGH. “RuBisCo maximises the chance that a CO2 molecule rather than a molecule of the much more abundant oxygen reacts with the substrate, by grabbing the biphosphate molecule and twisting it The trade-off is that this twisting makes it hard for RuBisCo to release the end product-hence its slowness. Arguably, RuBisCo is not inefficient, it's as good as it could get.” http://answersinscience.org/EvolGreatestMistakes-NewSci%20081107.pdf View in LinkedIn

GREAT OXYGENATION EVENT. “RuBisCo's failings have been attributed to the fact that when it evolved, levels of oxygen were far lower than they are now, so mistaking oxygen for CO2 would have mattered far less. Research published last year, however, suggests that far from being a dunce, RuBisCo has a streak of genius. O2 and CO2 have some similar physical features that make it hard for any enzyme to discriminate between them.” http://answersinscience.org/EvolGreatestMistakes-NewSci%20081107.pdf View in LinkedIn

ENZYMATIC RATES. “RuBisCo "fixes" CO2 by attaching it to a sugar called ribulose bisphosphate. But it is easily confused, and sometimes picks up an oxygen molecule and attaches that instead, causing a series of reactions that result in the loss of both carbon and energy. Worse still, RuBisCo enzymes catalyse the reaction of only about three molecules per second. Other common enzymes catalyse tens of thousands.” http://answersinscience.org/EvolGreatestMistakes-NewSci%20081107.pdf View in LinkedIn

CONFOUNDING FUNCTION. “Nearly all life on Earth depends upon the enzyme called RuBisCo. It turns carbon dioxide from the air into the chains of carbon that are the building blocks of all life. But as well as being one of the world's most sluggish enzymes, it is apparently too stupid to tell the difference between carbon dioxide and oxygen. If this isn't one of evolution's greatest mistakes, then what is?” https://lnkd.in/euYr6Cx View in LinkedIn

CAVEAT. “We should not confuse the properties of an example of a phenomenon with the phenomenon itself: complexity increase is not synonymous with adaptionist natural selection.” https://lnkd.in/euEN3Eh View in LinkedIn

OTHERS VERY EFFICIENT. “Certainly Rubisco seems to be the exception amongst enzymes, many of which (such as the convergently evolved carbonic anhydrase) seem to verge on the unbelievable in their efficiency.” https://lnkd.in/euEN3Eh View in LinkedIn

LOW COMPLEXITY START. “Such systems are typically modeled as localized individuals that reproduce in an error-prone process, with their offspring weeded out in competitions with other individuals that select for higher complexity. In this natural selection process the individuals in a line of biological descent increase their complexity in time.” https://lnkd.in/euEN3Eh View in LinkedIn

AT THE EFFICIENCY LIMIT? “It may be that Rubisco is as good as it can get; as Tcherkez et al. note “all ribulose bisphosphate carboxylases may be near perfectly optimized”. Such examples as Rubisco are a useful reminder of some under-appreciated realities: even what appears to be disastrously maladaptive – who, after all would design an enzyme that is disabled by the very substance (oxygen) it helps to produce? – may still be as good as is possible.” https://lnkd.in/euEN3Eh View in LinkedIn

STARTING POINT. “It seems that many systems both increase their complexity if initialized in a low complexity state, and then reliably and robustly maintain high (but finite) complexity once it is attained. Some of the most prominent examples are the many biological systems undergoing natural selection that seem to start with low complexity and then increase their complexity.” https://lnkd.in/euEN3Eh View in LinkedIn

ENZYME LIMITS. “Take the protein Rubisco, of central importance in photosynthesis where as a carboxylase it acts as the enzyme central to the fixation of carbon. Yet, as is well-known, its rate of activity is cripplingly slow, explaining why it is the most abundant protein on the planet. It is difficult to think of an example where even a modest improvement in efficiency would not be adaptively highly significant, yet the only solution appears to be by rampantly convergent methods of carbon dioxide concentration, be they by carboxysomes.” https://lnkd.in/euEN3Eh View in LinkedIn