scholarly journals Type II Toxin–Antitoxin Systems in the Unicellular Cyanobacterium Synechocystis sp. PCC 6803

Toxins ◽  
2016 ◽  
Vol 8 (7) ◽  
pp. 228 ◽  
Author(s):  
Stefan Kopfmann ◽  
Stefanie Roesch ◽  
Wolfgang Hess
Keyword(s):  
Type Ii ◽  
Unicellular Cyanobacterium ◽  
Synechocystis Sp ◽  
Pcc 6803

scholarly journals Biochemical elucidation of citrate accumulation in Synechocystis sp. PCC 6803 via kinetic analysis of aconitase

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Maki Nishii ◽  
Shoki Ito ◽  
Noriaki Katayama ◽  
Takashi Osanai
Keyword(s):  
Kinetic Analysis ◽  
Chemical Equilibrium ◽  
Isocitrate Dehydrogenase ◽  
Tca Cycle ◽  
Tricarboxylic Acid ◽  
Unicellular Cyanobacterium ◽  
Citrate Accumulation ◽  
Kinetics Of ◽  
Synechocystis Sp ◽  
Pcc 6803

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.

scholarly journals Type II Isopentenyl Diphosphate Isomerase from Synechocystis sp. Strain PCC 6803

2004 ◽  
Vol 186 (23) ◽  
pp. 8156-8158 ◽  
Author(s):  
Sam J. Barkley ◽  
Shrivallabh B. Desai ◽  
C. Dale Poulter
Keyword(s):  
Escherichia Coli ◽  
Open Reading Frame ◽  
Flavin Mononucleotide ◽  
Isopentenyl Diphosphate ◽  
Type Ii ◽  
Isopentenyl Diphosphate Isomerase ◽  
Reading Frame ◽  
Synechocystis Sp ◽  
Pcc 6803

ABSTRACT Open reading frame sll1556 in the cyanobacterium Synechocystis sp. strain 6803 encodes a putative type II isopentenyl diphosphate (IPP) isomerase. The His6-tagged protein was produced in Escherichia coli and purified by Ni2+ chromatography. The homotetrameric enzyme required NADPH, flavin mononucleotide, and Mg2+ for activity; K m IPP was 52 μM, and k cat IPP was 0.23 s−1.

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