2-Oxoglutarate levels control adenosine nucleotide binding by Herbaspirillum seropedicae PII proteins

9Citations
Citations of this article
17Readers
Mendeley users who have this article in their library.

This article is free to access.

Abstract

Nitrogen metabolism in Proteobacteria is controlled by the Ntr system, in which PII proteins play a pivotal role, controlling the activity of target proteins in response to the metabolic state of the cell. Characterization of the binding of molecular effectors to these proteins can provide information about their regulation. Here, the binding of ATP, ADP and 2-oxoglutarate (2-OG) to the Herbaspirillum seropedicae PII proteins, GlnB and GlnK, was characterized using isothermal titration calorimetry. Results show that these proteins can bind three molecules of ATP, ADP and 2-OG with homotropic negative cooperativity, and 2-OG binding stabilizes the binding of ATP. Results also show that the affinity of uridylylated forms of GlnB and GlnK for nucleotides is significantly lower than that of the nonuridylylated proteins. Furthermore, fluctuations in the intracellular concentration of 2-OG in response to nitrogen availability are shown. Results suggest that under nitrogen-limiting conditions, PII proteins tend to bind ATP and 2-OG. By contrast, after an ammonium shock, a decrease in the 2-OG concentration is observed causing a decrease in the affinity of PII proteins for ATP. This phenomenon may facilitate the exchange of ATP for ADP on the ligand-binding pocket of PII proteins, thus it is likely that under low ammonium, low 2-OG levels would favor the ADP-bound state. Binding of ATP, ADP and 2-oxoglutarate (2-OG) to uridylylated and non-uridylylated Herbaspirillum seropedicae PII proteins was characterized and intracellular 2-OG quantified. PII proteins bound three molecules of each ligand, and 2-OG stabilized ATP binding. Variation in the intracellular concentration of 2-OG in response to nitrogen was measured and it can be related to a decrease in affinity of PII for ATP.

Cite

CITATION STYLE

APA

Oliveira, M. A. S., Gerhardt, E. C. M., Huergo, L. F., Souza, E. M., Pedrosa, F. O., & Chubatsu, L. S. (2015). 2-Oxoglutarate levels control adenosine nucleotide binding by Herbaspirillum seropedicae PII proteins. FEBS Journal, 282(24), 4797–4809. https://doi.org/10.1111/febs.13542

Register to see more suggestions

Mendeley helps you to discover research relevant for your work.

Already have an account?

Save time finding and organizing research with Mendeley

Sign up for free