Mathias Gschell
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Ammonium sensors -
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Abstract
The ammonium sensor Sd-Amt1 from the marine bacterium Shewanella denitrificans is one of many alterations of the nearly ubiquitous Ammonium transport (Amt) proteins. In contrast to its Amt homologs, Sd-Amt1 does not mediate the transport of ammonium ions across membranes but diverges them to a remodeled internal pocket that specifically binds two ammonium cations.
Additionally, Sd-Amt1 possesses a cytosolic effector domain, precisely a diguanylate cyclase (DGC) domain that converts two molecules of GTP to the second messenger molecule cyclic di-GMP.
Our primary goal is to solve the three-dimensional structure of the entire protein and to understand the mechanistic details of signal reception and transduction events.
Methods
Protein expression and purification, detergent- and polymer-based membrane solubilisation, enzymatic assays, protein crystallization and cryo EM structure determination.
