Path followed
1. Are there any external resources that can be used by the damaged component?
Answer: No
2. Is there any foreign material present?
Answer: No
3. Can the repair begin without an external energy resource?
Answer: No
4. Is there a trigger event to begin the repair?
Answer: Yes
5. Does the healing change the characteristics of the system?
Answer: No
11) Photosynthetic systems rapidly disassemble and reform. Rhodobacter sphaeroides.
Damaged sections of photosynthetic protein complexes in plants and bacteria are repaired via an internal cellular system of recognition, removal, and repair. The molecular components of nature’s photosynthetic machinery take a beating from high-energy photons, ultraviolet light, and highly oxidizing (i.e., degrading) byproducts. When damage occurs, cellular processes recognize and cut off the damaged part of photosynthetic protein complex, remove the intact section to the outer regions of the cell where it can be fully repaired, and then return to its original site and function.
Self-repair processes in plants, algae and photosynthetic bacteria use molecular recognition and metastable thermodynamic states to make protein complexes that can be continually repaired by partial disassembly and reassembly with new components, initiated by chemical signals alone. For example, the repair of protein D1 in photosystem II (PS II) when photodamaged is initiated by photoinactivation of the protein induced by both the acceptor side and the donor side. This results in peptide bond scissions that alter protein conformation and drive dissociation of the damaged complex from the large PS II assemblies embedded within membrane stacks inside the chloroplast of a plant cell1. The separated complex diffuses laterally from within the stacks of membranes and out towards the outer membrane regions, where it disassembles into peripheral lightharvesting complex II (LHC II) and a PS II core complex2. The damaged D1 component of the PS II core is then fully degraded and the depleted complex equilibrates with newly biosynthesized D1 protein, resulting in the self-assembly of a tightly bound, repaired complex. The repaired complex returns to within the membrane stacks, where it re-docks with the extended light-harvesting systems inside the membranes, thus completing the repair cycle1. Central to this self-repair process are molecular recognition of the components and thermodynamic metastability, which allow the system to reversibly transition between kinetically trapped and disassembled states.
AskNature. ÒPhotosynthetic systems rapidly disassembles and reforms.Ó 10 Mar 2015. Web. 28 Sept 2017.
https://asknature.org/strategy/photosynthetic-systems-rapidly-disassembles-and-reforms/#.Wc1qQkyZOu4
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