Miscellany: more plant process complexity (General)

by David Turell , Thursday, October 07, 2021, 19:55 (1141 days ago) @ David Turell

A complex plant process:

https://evolutionnews.org/2021/10/the-molecular-machine-behind-carbon-balance/

"What rubisco actually does is complicated. Rubisco grabs a CO2 molecule (most of the time) and attaches it to a sugar chain. (Bathellier et al. 2018) Rubisco then takes the lengthened carbon chain and clips it, thus producing two identical phosphoglycerate molecules. (PDB-101 Molecule of the Month) Making identical molecules is advantageous because then only a single set of enzymes is required for the remainder of the pathway. Additionally, phosphoglycerate is a highly familiar molecule to the cell. Most of the molecules will be fed back into the carbon fixation cycle, but some of them will also be siphoned off to produce sugars. Every bite of food you have ever taken is directly or indirectly the result of this amazing enzyme.

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"rubisco is nothing short of an incredible design, as validated by its abundance in the ecosystem, engineers’ inability to drastically improve it after fifty+ years of study, and its ability to pull CO2 out of the atmosphere, balancing the atmosphere.

"As I’ve indicated, plants are icons of sustainability. They create critical products for other living organisms while utilizing waste products — every environmental engineer’s dream design. Are these ecosystem-level designs mere coincidences of Darwinism? Can consideration of ecosystem constraints really occur without foresight? "

Comment: The article is a complex discussion of why this enzyme works so slowly. The purpose is not clear, as enzymes usually speed up reactions. Just offered as another example of complex design not possible by chance.