scholarly journals Global proteomic response of unicellular cyanobacterium Synechocystis sp. PCC 6803 to fluctuating light upon CO 2 step‐down

2021 ◽  
Author(s):  
Henna Mustila ◽  
Dorota Muth‐Pawlak ◽  
Eva‐Mari Aro ◽  
Yagut Allahverdiyeva
2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Maki Nishii ◽  
Shoki Ito ◽  
Noriaki Katayama ◽  
Takashi Osanai

AbstractA unicellular cyanobacterium Synechocystis sp. PCC 6803 possesses a unique tricarboxylic acid (TCA) cycle, wherein the intracellular citrate levels are approximately 1.5–10 times higher than the levels of other TCA cycle metabolite. Aconitase catalyses the reversible isomerisation of citrate and isocitrate. Herein, we biochemically analysed Synechocystis sp. PCC 6803 aconitase (SyAcnB), using citrate and isocitrate as the substrates. We observed that the activity of SyAcnB for citrate was highest at pH 7.7 and 45 °C and for isocitrate at pH 8.0 and 53 °C. The Km value of SyAcnB for citrate was higher than that for isocitrate under the same conditions. The Km value of SyAcnB for isocitrate was 3.6-fold higher than the reported Km values of isocitrate dehydrogenase for isocitrate. Therefore, we suggest that citrate accumulation depends on the enzyme kinetics of SyAcnB, and 2-oxoglutarate production depends on the chemical equilibrium in this cyanobacterium.


Toxins ◽  
2016 ◽  
Vol 8 (7) ◽  
pp. 228 ◽  
Author(s):  
Stefan Kopfmann ◽  
Stefanie Roesch ◽  
Wolfgang Hess

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