Paper Citing NAMD - Abstract
Ishitani, Ryuichiro; Sugita, Yuji; Dohmae, Naoshi; Furuya, Noritaka; Hattori, Motoyuki; Nureki, Osamu
Mg2+-sensing mechanism of Mg2+ transporter MgtE probed by molecular dynamics study
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 105:15393-15398, OCT 7 2008
Proper regulation of the intracellular ion concentration is essential to maintain life and is achieved by ion transporters that transport their substrates across the membrane in a strictly regulated manner. MgtE is a Mg2+ transporter that may function in the homeostasis of the intracellular Mg2+ concentration. A recent crystallographic study revealed that its cytosolic domain undergoes a Mg2+-dependent structural change, which is proposed to gate the ion-conducting pore passing through the transmembrane domain. However, the dynamics of Mg2+ sensing, i.e., how MgtE responds to the change in the intracellular Mg2+ concentration, remained elusive. Here we performed molecular dynamics simulations of the MgtE cytosolic domain. The simulations successfully reproduced the structural changes of the cytosolic domain upon binding or releasing Mg2+, as well as the ion selectivity. These results suggested the roles of the IN and CBS domains in the cytosolic domain and their respective Mg2+ binding sites. Combined with the current crystal structures, we propose an atomically detailed model of Mg2+ sensing by MgtE.
