Publication Details (including relevant citation information):
Proteins (2010) 78: 487-491.
Ragumani S, Sauder JM, Burley SK, Swaminathan S
Magnesium (Mg2+) is an essential element for growth and maintenance of living cells. It acts as a cofactor for many enzymes and is also essential for stability of the plasma membrane. There are two distinct classes of magnesium transporters identified in bacteria that convey Mg2+ from periplasm to cytoplasm [ATPase-dependent (MgtA and MgtB) and constitutively active (CorA and MgtE)]. Previously published work on Mg(2+) transporters yielded structures of full length MgtE from Thermus thermophilus, determined at 3.5 Å resolution, and its cytoplasmic domain with and without bound Mg2+ determined at 2.3 and 3.9 Å resolution, respectively [Hattori, 2007]. Here, we report the crystal structure of the Mg(2+) bound form of the cytosolic portion of MgtE (residues 6-262) from Enterococcus faecalis at 2.2 Å resolution. The present structure and magnesium bound cytosolic domain structure from T. thermophilus (PDB ID: 2YVY) are structurally similar. Three magnesium binding sites are common to both MgtE full length and the present structure. Our work revealed an additional Mg(2+) binding site in the E. faecalis structure. In this report, we discuss the functional significance of Mg(2+) binding sites in the cytosolic domains of MgtE transporters.
Address (URL): http://www.ncbi.nlm.nih.gov/pubmed/19787770