Biological complexity: cyanobacteria anatomy (Introduction)

by David Turell , Saturday, September 10, 2022, 17:50 (595 days ago) @ David Turell

How it supports photosynthesis:

https://www.sciencedaily.com/releases/2022/09/220909160338.htm

"Published Aug. 31 in the journal Nature, the findings immediately shed new light on microbial photosynthesis -- specifically, how light energy is captured and sent to where it's needed to power the conversion of carbon dioxide into sugars

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"The cyanobacterial antenna structures, which are called phycobilisomes, are complex collections of pigments and proteins, which assemble into relatively massive complexes.

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"One surprise, for example, came in how a relatively small protein can act as a surge protector for the massive antenna. Before this work, researchers knew the phycobilisome could corral molecules called orange carotenoid proteins, or OCPs, when the phycobilisome had absorbed too much sunlight. The OCPs release the excess energy as heat, protecting a cyanobacterium's photosynthetic system from burning up.

"Until now, there's been debate about how many OCPs the phycobilisome could bind and where those binding sites were. The new research answers these fundamental questions and offers potentially practical insights.

"This kind of surge-protecting system -- which is called photoprotection and has analogs in the plant world -- naturally tends to be wasteful. Cyanobacteria are slow to turn their photoprotection off after it has done its job. Now, with the complete picture of how the surge protector works, researchers can design ways to engineer "smart," less wasteful photoprotection, Kerfeld said.

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"'If you think of this like Legos, you can keep building up, right? The proteins and pigments are like blocks making the phycobilisome, but then that's part of the photosystem, which is in the cell membrane, which is part of the entire cell," Sutter said. "We're climbing up the ladder of scale in a way. We've found something new on our rung, but we can't say we've got the system settled.'"

Comment: unfortunately, I cannot look at the article itself to see the architecture. Just more indication of extreme complexity requiring design.