Alexander J. Ninfa

Regulation of Autophosphorylation of Escherichia coli Nitrogen Regulator II by the PII Signal Transduction Protein

Jiang, Peng, Ninfa, Alexander J.

The nitrogen regulator II (NRII or NtrB)-NRI (NtrC) two-component signal transduction system regulates the transcription of nitrogen-regulated genes in Escherichia coli. The NRII protein has both...

Activation of the glnA, glnK, and nac Promoters as Escherichia coli Undergoes the Transition from Nitrogen Excess Growth to Nitrogen Starvation

Atkinson, Mariette R., Blauwkamp, Timothy A., Bondarenko, Vladamir, Studitsky, Vasily, Ninfa, Alexander J.

The nitrogen-regulated genes and operons of the Ntr regulon of Escherichia coli are activated by the enhancer-binding transcriptional activator NRI∼P (NtrC∼P). Here, we examined the activation of...

Context-Dependent Functions of the PII and GlnK Signal Transduction Proteins in Escherichia coli

Atkinson, Mariette R., Blauwkamp, Timothy A., Ninfa, Alexander J.

Two closely related signal transduction proteins, PII and GlnK, have distinct physiological roles in the regulation of nitrogen assimilation. Here, we examined the physiological roles of PII and GlnK...

Genetic and Biochemical Analysis of Phosphatase Activity of Escherichia coli NRII (NtrB) and Its Regulation by the PII Signal Transduction Protein

Pioszak, Augen A., Ninfa, Alexander J.

Mutant forms of Escherichia coli NRII (NtrB) were isolated that retained wild-type NRII kinase activity but were defective in the PII-activated phosphatase activity of NRII. Mutant strains were...

A protein-induced DNA bend increases the specificity of a prokaryotic enhancer-binding protein

Dworkin, Jonathan, Ninfa, Alexander J., Model, Peter

Control of transcription in prokaryotes often involves direct contact of regulatory proteins with RNA polymerase from binding sites located adjacent to the target promoter. Alternatively, in the case...

Mutations Altering the N-Terminal Receiver Domain of NRI (NtrC) That Prevent Dephosphorylation by the NRII-PII Complex in Escherichia coli

Pioszak, Augen A., Ninfa, Alexander J.

The phosphorylated form of NRI is the transcriptional activator of nitrogen-regulated genes in Escherichia coli. NRI∼P displays a slow autophosphatase activity and is rapidly dephosphorylated by...

Regulation of Autophosphorylation of Escherichia coli Nitrogen Regulator II by the PII Signal Transduction Protein

Jiang, Peng, Ninfa, Alexander J.

The nitrogen regulator II (NRII or NtrB)-NRI (NtrC) two-component signal transduction system regulates the transcription of nitrogen-regulated genes in Escherichia coli. The NRII protein has both...

Activation of the glnA, glnK, and nac Promoters as Escherichia coli Undergoes the Transition from Nitrogen Excess Growth to Nitrogen Starvation

Atkinson, Mariette R., Blauwkamp, Timothy A., Bondarenko, Vladamir, Studitsky, Vasily, Ninfa, Alexander J.

The nitrogen-regulated genes and operons of the Ntr regulon of Escherichia coli are activated by the enhancer-binding transcriptional activator NRI∼P (NtrC∼P). Here, we examined the activation of...

Context-Dependent Functions of the PII and GlnK Signal Transduction Proteins in Escherichia coli

Atkinson, Mariette R., Blauwkamp, Timothy A., Ninfa, Alexander J.

Two closely related signal transduction proteins, PII and GlnK, have distinct physiological roles in the regulation of nitrogen assimilation. Here, we examined the physiological roles of PII and GlnK...

Genetic and Biochemical Analysis of Phosphatase Activity of Escherichia coli NRII (NtrB) and Its Regulation by the PII Signal Transduction Protein

Pioszak, Augen A., Ninfa, Alexander J.

Mutant forms of Escherichia coli NRII (NtrB) were isolated that retained wild-type NRII kinase activity but were defective in the PII-activated phosphatase activity of NRII. Mutant strains were...

A protein-induced DNA bend increases the specificity of a prokaryotic enhancer-binding protein

Dworkin, Jonathan, Ninfa, Alexander J., Model, Peter

Control of transcription in prokaryotes often involves direct contact of regulatory proteins with RNA polymerase from binding sites located adjacent to the target promoter. Alternatively, in the case...

Mutations Altering the N-Terminal Receiver Domain of NRI (NtrC) That Prevent Dephosphorylation by the NRII-PII Complex in Escherichia coli

Pioszak, Augen A., Ninfa, Alexander J.

The phosphorylated form of NRI is the transcriptional activator of nitrogen-regulated genes in Escherichia coli. NRI∼P displays a slow autophosphatase activity and is rapidly dephosphorylated by...

Modular cell biology: retroactivity and insulation

Del Vecchio, Domitilla, Ninfa, Alexander J, Sontag, Eduardo D

Modularity plays a fundamental role in the prediction of the behavior of a system from the behavior of its components, guaranteeing that the properties of individual components do not change upon...

Rate constants rather than biochemical mechanism determine behaviour of genetic clocks

Conrad, Emery, Mayo, Avraham E., Ninfa, Alexander J., Forger, Daniel B.

Many biological systems contain both positive and negative feedbacks. These are often classified as resonators or integrators. Resonators respond preferentially to oscillating signals of a particular...