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Fig. 1 | Microbial Cell Factories

Fig. 1

From: Metabolic pathway engineering using the central signal processor PII

Fig. 1

The strategy of metabolic engineering of the PII(I86N) protein in Synechocystis sp. PCC 6803 for arginine/cyanophycin overproduction. The conversion of N-acetylglutamate (Ac-Glu) to N-acetylglutamate-phosphate (Ac-Glu-P) is the rate-limiting step in the cyclic arginine synthesis pathway and is catalyzed by NAGK. NAGK activity is controlled by complex formation with the PII protein, which senses the nitrogen status by 2-oxogluterate (2-OG) binding. In the wild-type, unbound NAGK has low activity (dashed line) and is highly susceptible to arginine feedback inhibition, whereas NAGK bound to the PII protein has high activity (solid black line) and much less sensitive towards arginine. The PII(I86N) variant of strain BW86 (in orange box) permanently binds to NAGK and strongly increases its activity (solid orange line) and relieves arginine feedback inhibition. When excess arginine (Arg) is produced cyanophycin is synthesized from arginine and aspartate (Asp in red)

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