Ligand binding in the conserved interhelical loop of CorA, a magnesium transporter from Mycobacterium tuberculosis.

ABSTRACT: CorA is a constitutively expressed magnesium transporter in many bacteria. The crystal structures of Thermotoga maritima CorA provide an excellent structural framework for continuing studies. Here, the ligand binding properties of the conserved interhelical loop, the only portion of the protein exposed to the periplasmic space, are characterized by solution nuclear magnetic resonance spectroscopy. Through titration experiments performed on the isolated transmembrane domain of Mycobacterium tuberculosis CorA, it was found that two CorA substrates (Mg2+ and Co2+) and the CorA-specific inhibitor (Co(III) hexamine chloride) bind in the loop at the same binding site. This site includes the glutamic acid residue from the conserved "MPEL" motif. The relatively large dissociation constants indicat

SUBMITTER: Hu J 

PROVIDER: S-EPMC2708858 | biostudies-literature | 2009 Jun

REPOSITORIES: biostudies-literature