Backbone Assignment of Phosphorylated Cytoplasmic Domain B of Mannitol Transporter IIMtl in Thermoanaerobacter Tengcongensis

The cytoplasmic domains A and B of the mannitol transporter enzyme II Mtl are covalently linked in Escherichia coli , but separately expressed in Thermoanaerobacter Tengcongensis . The phosphorylation of domain B ( Tt IIB Mtl ) substantially increases the binding affinity to the domain A ( Tt IIA Mtl ) in T. Tengcongensis . To understand the structural basis of the enhanced domain - domain interaction by protein phosphorylation, we obtained NMR backbone assignments of the phospho- Tt IIB Mtl using a standard suite of triple resonance experiments. Our results will be useful to monitor chemical shift changes at the active site of phosphorylation and the binding interfaces.