Analysis Biomolecular Interactions of PirC and PII by BLI (CAT#: STEM-MB-0220-CJ)

Introduction

Nitrogen limitation causes a major shift in the lifestyle of non-diazotrophic cyanobacteria, which is controlled by a complex interplay of regulatory factors involving the universal signal processor PII. Once nitrogen limitation is achieved, the newly fixed carbon is immediately redirected towards glycogen synthesis.

Using the non-diazotrophic cyanobacterium Synechocystis sp. PCC 6803 as a model system, a new PII interactor, PirC, the product of the sll0944 gene, was identified. pirC binds to and inhibits the activity of 2,3-phosphoglycerate independent phosphoglycerate mutase (PGAM), an enzyme that deflects newly fixed CO2 towards low glycolysis. The binding of PirC to PII or PGAM is regulated by the metabolite 2-oxoglutarate (2-OG), which accumulates during nitrogen starvation. Mutants lacking pirc have significantly reduced glycogen levels and excessive accumulation of polyhydroxybutyrate particles during nitrogen deprivation. It was shown that pirC can control carbon fluxes in cyanobacteria through mutually exclusive interactions with PII or PGAM.