6gpv
Crystal structure of blue-light irradiated miniSOG
Structural highlights
Function[PHOT2_ARATH] Protein kinase that acts as a blue light photoreceptor in a signal-transduction pathway for photo-induced movements. Mediates calcium spiking of extra- and intracellular origins in response to blue light. Involved in hypocotyl phototropism. Contributes to the chloroplast accumulation in low blue light and mediates their translocation (avoidance response) at high fluence. Regulates stomata opening and photomorphogenesis response of leaf tissue. Not involved in hypocotyl elongation inhibition, anthocyanin accumulation or cotyledon opening.[1] [2] [3] [4] [5] Publication Abstract from PubMedminiSOG is the first flavin-binding protein that has been developed with the specific aim of serving as a genetically-encodable light-induced source of singlet oxygen ((1)O2). We have determined its 1.17 A resolution structure, which has allowed us to investigate its mechanism of photosensitization using an integrated approach combining spectroscopic and structural methods. Our results provide a structural framework to explain the ability of miniSOG to produce (1)O2 as a competition between oxygen- and protein quenching of its triplet state. In addition, a third excited-state decay pathway has been identified that is pivotal for the performance of miniSOG as (1)O2 photosensitizer, namely the photo-induced transformation of flavin mononucleotide (FMN) into lumichrome, which increases the accessibility of oxygen to the flavin FMN chromophore and makes protein quenching less favourable. The combination of the two effects explains the increase in the (1)O2 quantum yield by one order of magnitude upon exposure to blue light. Besides, we have identified several surface electron-rich residues that are progressively photo-oxidized, further contributing to facilitate the production of (1)O2. Our results help reconcile the apparent poor level of (1)O2 generation by miniSOG and its excellent performance in correlative light and electron microscopy experiments. Tailing miniSOG: structural bases of the complex photophysics of a flavin-binding singlet oxygen photosensitizing protein.,Torra J, Lafaye C, Signor L, Aumonier S, Flors C, Shu X, Nonell S, Gotthard G, Royant A Sci Rep. 2019 Feb 20;9(1):2428. doi: 10.1038/s41598-019-38955-3. PMID:30787421[6] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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