Structures of the cyanobacterial nitrogen regulators NtcA and PipX complexed to DNA shed light on DNA binding by NtcA and implicate PipX in the recruitment of RNA polymerase.

ABSTRACT: The CRP-FNR (cAMP receptor protein-fumarate/nitrate reductase regulator) superfamily of transcriptional regulators includes the cyanobacterial master regulator NtcA, which orchestrates large responses of cyanobacteria to nitrogen scarcity. NtcA uses as allosteric activator 2-oxoglutarate (2OG), a signal of nitrogen poorness and carbon richness, and binds a co-activating protein (PipX) that shuttles between the signaling protein PII and NtcA depending on nitrogen richness, thus connecting PII signaling and gene expression regulation. Here, combining structural (X-ray crystallography of six types of crystals including NtcA complexes with DNA, 2OG, and PipX), modeling, and functional [electrophoretic mobility shift assays and bacterial two-hybrid (BACTH)] studies, we clarify the reasons for t

SUBMITTER: Forcada-Nadal A 

PROVIDER: S-EPMC11850224 | biostudies-literature | 2025 Feb

REPOSITORIES: biostudies-literature