Fernando Ormeno
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Structure and function of Ammonium Transporter 2 from Archaeoglobus fulgidus and interaction with its regulatory partner GlnK2Principal investigator: Prof. Dr. Oliver Einsle Institute for Biochemistry Phone: +49 (0) 761 203 6054 |
Abstract
The Ammonium Transporter 2 (Af-Amt2) encoded in the genome of the hyperthermophile euryarchaeon Archaeoglobus fulgidus forms a protein complex with Af-GlnK2 protein. In homologue proteins, GlnK binds to ADP which promotes conformational changes enabling the interaction with Amt that prevents ammonium uptake into the cytoplasm. Conversely, ATP and 2-oxoglutarate binding to GlnK are signals for GlnK:Amt complex dissociation. Although, the analysis of ligand binding to Af-GlnK2 confirmed the expected nucleotide recognition, intriguingly revealed a unique incapacity of Af-GlnK2 to recognize 2-oxoglutarate. Moreover, the characterization of Amt homologue proteins that carry out a sensor function of ammonium, allowed us to identify, by amino acid sequence comparisons, the presence of two potential binding pockets for ammonium in Af-Amt2. In this research, we investigate the conditions for the GlnK2:Amt2 complex formation, as well as the assembly structure in order to have insights about its functionality for the ammonium homeostasis.
Methods
Protein expression and purification, X-ray crystallography, right-angle light scattering, isothermal titration calorimetry, solid-supported membrane-based electrophysiology
